Midway through Mayor Marion Barry's second term, District residents overwhelmingly approve of Barry's job performance, according to a recent Washington Post survey. But residents are less convinced that Barry can bring a high ethical standard to city government.

The poll, conducted in early December, showed that 65 percent of D.C. residents felt Barry was doing a good or excellent job as mayor, while 51 percent approved of what he is doing to ensure that top D.C. government officials maintain a high ethical standard.

Some 32 percent of those surveyed indicated they disapproved of Barry's ethical standards in government. About 48 percent of those interviewed said they thought Barry cares equally about the needs of all residents, compared with 38 percent who said Barry favors special interests. The rest said they weren't sure.

The Post survey of 836 adults was conducted Dec. 9 to 14, near the end of one of Barry's most trying years in office.

The poll was completed prior to reports that former deputy mayor Ivanhoe Donaldson, Barry's most trusted political adviser, is under investigation by a federal grand jury for possible misuse of city funds while he headed the D.C. Department of Employment Services.

When asked how they would rate the job Barry is doing as mayor, 54 percent said he was doing a good job and 11 percent said an excellent job, compared with 15 percent who said his performance was not good and 11 percent who said it was poor. The rest of the respondents said they were not sure.

The mayor fared slightly better among blacks than whites on this question and did somewhat better among women than men.

However, on the question of ethics in government, Barry's approval rating dropped off. Of those interviewed, 43 percent said they thought he has done a good job and 8 percent said he has done an excellent job.

The question asked on the ethics issue was: "How about the job Barry is doing to make sure top District government officials have high ethical standards?"

Last year, Barry's name surfaced in a federal grand jury investigation of drug use by city employes that led to the conviction of Karen Johnson, a former mid-level employe of the D.C. Office of Energy. Barry's lawyer acknowledged that the mayor had a "personal relationship" with Johnson. Barry testified before the grand jury last January but has not been charged with any wrongdoing.

U.S. Attorney Joseph E. diGenova also launched grand jury investigations of the D.C. Department of Housing and Community Development for alleged mishandling of government funds in carrying out the Bates Street housing project, and of the Department of Employment Services.

In an interview this week, Barry said that his personal and political popularity is "at an all-time high." Although there may be occasional problems with his administration, he said, few people seriously question his integrity.

"The great majority of the people first of all believe I'm personally honest," he said. "They believe I have great integrity. They believe I tell the truth. And they believe I don't tolerate corruption in government.

"And when you look at the real hard instances of what has happened since I've been mayor, six years, you find some instances of poor management, you find people make mistakes, you find a decision is not the best decision to make, but you don't find a system where developers think they can come by city hall and give somebody some money and pay their way off to get a contract or permit," he said.

Last year, a number of embarrassing episodes raised questions about the integrity of the city government.

Mildred Bautista, former executive director of the D.C. Commission on the Arts and Humanities, was convicted and placed on three years' probation in connection with charges she stole more than $23,000 in commission funds.

Antonio Ruiz resigned as executive director of the city's cable television design commission after Johnson's indictment disclosed that he helped her arrange a cocaine sale.

Two employes of the Department of Employment Services and a private contractor were fired after the mayor publicly confirmed that they had misused city funds. Also, Barry's administration was sharply criticized by D.C. Auditor Otis Troupe for having parceled out lucrative consulting contracts to former city officials.

Last month, The Post reported that the federal grand jury was investigating Donaldson, the mayor's one-time aide and currently chairman of the D.C. Democratic State Committee. Sources said the grand jury is focusing on about $30,000 in city government checks issued during Donaldson's tenure as head of the Department of Employment Services.

Barry has declined to comment directly on the Donaldson investigation. However, referring to the several ongoing investigations, Barry said this week that "the mere fact that you investigate something does not mean there's major corruption there."

Among the D.C. residents surveyed who disapprove of Barry's efforts to achieve a high ethical standard in the government, whites clearly are more critical of the mayor than are blacks and men are more critical than women.

Among the white residents interviewed, 42 percent disapproved of Barry's performance compared with 27 percent of the black residents surveyed. Nearly 36 percent of men interviewed said Barry's performance was poor or not good, compared with 29 percent of the women who held similar views.

Barry said his own private polling indicates his personal popularity is very high.

"Obviously, I've got detractors," said Barry, who has indicated that he plans to seek a third four-year term in 1986. "But my popularity -- personal popularity and political popularity -- is at an all-time high."