Patricia Roberts Harris is running. On a recent Thursday night, she was in the Penn-Branch section of Southeast for wine and cheese with about 85 people. Three days later, she spoke at People's Congregational Church in Crestwood, where 500 people broke church decorum to stand and applaud her.

Last Tuesday night, she was back across the Anacostia River in Congress Heights. The snow slowed her down Thursday, wiping out a scheduled appearance in Brookland. But she was in church again last Sunday, this time at St. Timothy's, an Episcopal church in Southeast across the the street from Mayor Marion Barry's house.

Despite all this running, Harris says she still has not made up her mind to run for mayor in the Sept. 14 Democratic primary. The former Carter cabinet member will only say that she is "obviously at the point of serious consideration."

"I am not a person who wastes time knowingly," Harris said when asked what conclusion should be drawn from her busy schedule. "I'm doing exactly what I say I'm doing. I'm talking to my friends and neighbors and ascertaining what their concerns for the District are . . . "

Harris, former secretary of Housing and Urban Development, former secretary of Health and Human Services, former ambassador to Luxembourg and former vice delegate to the United Nations, is the first person of such national stature to show an interest in being mayor of the District of Columbia.

"If Atlanta can have Andy Young, why can't Washington, D.C., have Pat Harris?" Harris supporter Jean Davis said at a recent reception for Harris in a middle-class enclave in Southeast. (Young was U.S. ambassador to the United Nations in the Carter administration.)

In private, Harris' face takes on a grin-and-bear-it look at that comment. She doesn't want anyone to think she wants the job just to keep herself in public life.

"The only reason I'm considering it is because I don't think Washington has ever worked as well as it could, before home rule or since home rule," the 57-year-old Harris says, "and I think a great deal of that is a question of leadership on the executive side . . .

"I am not going to criticize the current executive. He's been here to her home in upper Northwest off 16th Street to lunch and he knows what my concerns are. You can assume I am not personally satisfied. You can't even get them to pick up a piece of furniture if you are throwing it away."

The field of challengers to Barry in the primary is crowded already. Council member John Ray has officially launched his campaign, Council members Betty Ann Kane, John A. Wilson and Charlene Drew Jarvis are at various other stages of pre-announcement candidacy and former council chairman Sterling Tucker has been trying for months to mount another campaign for mayor. Tucker lost in 1978.

Harris could be expected to draw her initial support from the large bloc of middle-class blacks who in the 1978 primary split their votes between Tucker and former mayor Walter E. Washington, allowing Barry to win the crucial Democratic nomination with a scant 35 percent of the vote.

But the best thing Harris has going for her, many of her supporters say, is that none of the other candidates has a background like hers.

A 1945 graduate of Howard University, Harris has made her home in Washington since 1949. From 1953 to 1959, she was executive director of Delta Sigma Theta, a predominantly black sorority. The fact that she is a woman in a city with mostly female and mostly black voters and has strong ties to a prominent black sorority is not lost on her political supporters.

In 1960, she received a law degree from George Washington University and within a year became dean of students and a lecturer in law at Howard University. That sort of fast career movement started Harris' reputation as an ambitious, hard-working woman who knew how to get ahead.

She became dean of Howard Law School in 1969 but quit after a dispute with the university's administration and joined a politically well-connected Washington law firm whose principals included Max Kampelman, a close associate of Hubert H. Humphrey.

In 1977, she was named secretary of HUD and in 1979 became secretary of the old Health, Education and Welfare department after Joseph A. Califano was fired following a dispute with Carter. Since leaving the administration, she has decided to take off a year and contemplate her future.

Harris' prominence has prompted as much skepticism as support.

"I don't know that Pat would really be interested in the job," says Herbert O. Reid, Barry's legal counsel and an old acquaintance of Harris. "She wouldn't be dealing with national issues or national people.

"The job is about making sure that people's trash gets collected. There's a question of whether she wants to work on that particular level. I kind of think she's not too serious," Reid said.

Barry declined several requests last week to discuss Harris' possible candidacy.

Another drawback from Harris' national reputation is the allegation that she is too upper-crust--too bourgeois--for the large population of working-class Washingtonians, and has no roots in local political activities, despite the fact that she was elected Democratic national committeewoman in 1977.

"People who run for public office should not surface suddenly and ask to be mayor," says City Council member H.R. Crawford (D-Ward 7), who was an assistant secretary at HUD in the Nixon administration. "The people of this city are not retarded. They know who has done things for this city."

In her nighttime meetings, Harris is regularly asked about the extent of her involvement in local life.

"How far do you want to go back?" Harris, speaking in a soft yet steely voice, asked a young man during a meeting in Congress Heights at the home of school board member R. Calvin Lockridge. "Do you want to go back to 1943 when I was in the sit-ins to integrate a restaurant on the northeast corner of 14th and U? . . . The most interesting thing I did was getting the department stores to employ black clerks at Garfinckel's and Hecht's."

The man who asked the question blurted out: "Then you got me a job, 'cause I used to work at Hecht's."

In an interview in her two-story brick house off upper 16th Street NW, Harris said she was not considering running for mayor until last January when she was asked to by a man whom she refuses to identify. In April, she says, a group was formed to ask her to run and in midsummer the group paid to have a poll done by Peter D. Hart Research Associates. Harris refuses to discuss the poll's findings.

Sources who have seen the poll say it indicates that she has good name recognition and that she is perceived as a capable, competent person who could make the much maligned city government work. The poll identified Barry as her major opponent, the sources said.

Harris said she virtually had decided not to run because most of the people urging her on seemed more interested in a good political fight than in what she would do as mayor. Some encouragement was coming from her former executive assistant at HUD, Henry Hubschman, a lawyer at Harris' former law firm, who says that he was getting repeated phone calls asking him to urge her to run.

Then in late December, she was asked to reconsider by a group that included Sharon Pratt Dixon, the D.C. Democratic national committeewoman; former City Council member Douglas E. Moore; Lockridge; Davis, a local political activist who once worked for Rep. Shirley Chisholm (D-N.Y.), and Barbara Bell Clark, vice chairman of the D.C. Democratic State Committee.

Harris' involvement with Lockridge and Moore has caused a rash of puzzled looks in political circles because Moore and Lockridge have had stormy public careers that contradict the image of polished political maturity that many find most attractive in Harris.

The most often cited explanation for such an alliance is that Harris needs them to take the edge off her image as one of the elite. Moore and Lockridge also have been bitter political foes of Barry. Harris says only that they came to her with real concern about the city and she listened.

According to Lockridge, the group that went to Harris' home in late December told her "she didn't have the right not to run and not give the people who live here a chance for better government."

Harris said she wanted to know if more people than those in the group felt that way. That is when the group agreed to arrange meetings for Harris with residents throughout the city. More than two dozen meetings have been set up.

Harris said she thinks she can raise enough money to run for mayor in the city--a race that could cost $500,000 or more, according to many city politicians.

She said enough key city politicians have promised support to make her feel that she could put together a good organization quickly, and she is encouraged, she said, by the responses she gets at meetings such as the one held last week at Lockridge's house a few blocks from Martin Luther King Avenue SE.

Harris, wearing a brown corduroy suit, entered the house shaking hands with a gentle touch and asking people to repeat their names. The message there was that she will make an effort to remember names.

Lockridge said he had invited about 20 people, but more than 70 showed up--an unusually large turnout for any political meeting in a ward where voter turnout is usually low.

Harris was asked about her background, as people crowded into the living room, where she was seated. "I come from longtime country people who made the trek across the country the way most black people made the trek . . . They went from Virginia to Illinois, a little town called Mattoon. That was the luckiest thing that happened because Mattoon, which was about as prejudiced as any place could be, didn't have enough black folks to have separate and inferior schools."

A woman asked in what direction a "Mayor Harris" would take the city. A smooth speaker, Harris took a rare poke at Barry: "I'm offended very frankly when people in charge say 'I can't do that--it's the bureaucracy.' You show me a bad bureaucrat and I'll show you bad supervision."

Harris stopped talking. The group waited. "I see these 'D.C. on the Grow' signs," she said. "D.C. on the grow for who, for what, for what purpose? " There was cheering and back slapping.

A woman asked Harris how she would deal with her image of being "bourgeois."

"Bourgeois? " said Harris. "I don't know what that is. We're the only people in the world who cut each other down for achieving, for being what everybody wants to be. Am I bourgeois for getting an education, for getting scholarships and using that to get the jobs I wanted? "

Many who attend the evening meetings with her say they are eager for her to announce. But Pat Harris will not be rushed.

"I do not want to be the entertainment for the six nights a week that 'Hill Street Blues' is not on television by joining the mayoralty race," she told the well-dressed crowd at Davis' house in Southeast.

"The District doesn't need to have the election turn into a circus for everyone to laugh at," she said. "There's too much of people going into positions on a personal ego trip. That might explain the quality of national leadership we have."