Marion Barry, describing himself as the only candidate with experience as a mayor, said yesterday that he deserves to be reelected because he knows the government better than any of his opponents and can handle the city's problems better than anyone who would succeed him.

During a wide-ranging, 90-minute interview with reporters, editors and editorial writers at The Washington Post, Barry said that in his first term he took control of the city's financial problems and can now begin programs to bring more jobs and housing to the city and to lower the rising crime rate.

"When you look at all the great mayors around the country -- like William Donald Schaefer in Baltimore -- where the city is blossoming into great things, the mayor has been there more than one term," said Barry, who was accompanied by his campaign manager, Ivanhoe Donaldson, and City Administrator Elijah B. Rogers.

Barry, one of four candidates seeking the Democratic nomination for mayor in the Sept. 14 primary, spent considerable time defending his first term in office with a flurry of statistics and repeated assertions that the city government is better run now than when he took office on Jan. 2, 1979:

* If reelected, he said, he would use $50 million to $100 million from the sale of city-owned urban renewal land to begin a development bank to offer low-interest loans for housing construction.

* Barry said he would not support a formula-based budget for the city's public schools unless the federal payment to the city government was also made on the basis of a formula.

* He said his administration has renovated nearly 3,000 units of public housing, not the 50 cited by one of his opponents, though he later acknowledged that many of those 3,000 renovations involved relatively minor repairs, such as replacement of broken windows.

* Barry said he would comply with congressional directives to hire about 130 more police officers, bringing the city's force to 3,880 -- the largest that he thinks the police department should be. He said the fact that he has consistently held down spending for the police department does not mean he is soft on crime.

Asked why he has refused to take part in some live televised debates that have been proposed for the final days of the campaign, Barry said the fact that there have been more than 80 candidate forums throughout the city minimized the need for such debates. He said he rejected an invitation for a one-on-one debate with his leading challenger, lawyer Patricia Roberts Harris, because it would have been unfair to the other two candidates in the Democratic primary -- City Council members John Ray and Charlene Drew Jarvis.

* And in the area of financial affairs, Barry said that the city would under no circumstances end the current fiscal year with a budget deficit and reaffirmed his assertion that there would be no layoffs of city employes if he is elected to a second term.

"I have a solid record, not only of making sure that our financial affairs are in order, but the future is even brighter in the sense that now that we have a handle on our finances, our income and our expenditures," Barry said.

"The bottom line in terms of the future over the next four years," he said, is that "our financial affairs and our budget have the best budget manager and the best team of managers of anyone."

Barry, wearing a dark blue pin-striped suit and appearing very self-confident throughout most of the interview, bristled when the talk turned to suggestions made by his opponents that he has found support for his reelection campaign through his awarding of city contracts, jobs and development rights to potential supporters.

"People are supporting me because of their belief in the future," he said. "and because they believe in my achievements. My supporters are too intelligent to be bought and personally I'm too honest and have high standards about myself. My broad support is based on my achievement."

Much of yesterday's discussion interview with the 46-year-old former activist, school board president and City Council member, centered on housing, which Barry had made a central issue during his 1978 campaign. On that subject, Barry said the city still needs help from the federal government to offer more money for loans and financing of home construction in the city.

"In the area of housing production, we had a record that surpasses any previous administration and surpasses most cities in the country in terms of the number of housing units produced," Barry said.

"Again for the future -- because I know better how to do it and know what instruments to use -- we can expect a major focus on housing production, renovation and new construction," he said.

Barry said his administration has spent more than $32 million and renovated more than 2,900 public-housing units, an unspecified number of which had primarily received repairs that brought them up to minimum housing code standards -- air conditioners, downspouts, new windows and new roofs, for instance.

He said another $18 million was budgeted for making improvements in public housing and that the city would break ground at East Capitol Dwellings for 500 more units of housing next week, seven days before the election.

Barry added that he has started a program of consulting public housing tenants about repairs to be made because if the tenants are not involved in the process, "they'll tear up that which is fixed up."

"So housing for the future in my administration will be very bright because we will have demonstrated our ability to do it," he said. "No rhetoric, no talk. These are the facts we're speaking about."

Recently, the D.C. auditor reported that the Barry administration had mismanaged $4 million spent in the Bates Street housing renovation project, which candidate Barry pledged in 1978 to finish if elected. The project has been riddled with delays and poor workmanship and 40 of the 163 units still have not been completed.

Yesterday, the mayor took issue with the auditor's assertion, saying his administration actually had rescued the project and he termed Bates Street a success.

On the regular battles he has had with the school board since coming into office, Barry said he has improved his relations with the school board since the Rev. David H. Eaton was elected president of the board this year.

He said he had the most problems with the board when R. Calvin Lockridge was president of the board last year.

"I had a terrible time with Mr. Lockridge quite frankly when he was president," he said. "But we don't have that anymore. We have a majority of board members who are collaborative and coordinative in their feelings and working with the superintendent." Lockridge is now field coordinator for the Harris campaign.

During most of his administration, Barry proposed holding the line on school spending, noting a declining enrollment and arguing that increased spending was not the answer to problems in the city's public schools.

One of Barry's opponents, Ray, supports a fixed formula for the schools to avoid yearly wrangling over the school budget involving the mayor, the council and the board.

But Barry said yesterday he opposes that idea until the federal payment, the federal government's annual payment to the city in lieu of taxes, is also on a fixed formula.

On the city budget, Barry said said his administration has a much more up-to-date assessment of the city's daily financial picture, receiving reports each afternoon. When he took office, he said, it took 14 telephone calls to obtain such information.

Barry dismissed complaints from Council members that he is hiding information on the city's spending and revenues. He said information on the budget is often voluminous and technical and some council members do not have the staff or time to understand the information.

Barry said that slowing rates of revenue growth posed a challenge to the government. But, he added, "Any factor, I can control better than anyone running against me for mayor. I'm intelligent, I've got the brainpower, I'm able to attract the brightest people to work for me. Look at the people in this room," he said, pointing to Donaldson and Rogers.

Generally, Barry said the delivery of basic city services has improved during his term in office. He called his Supercan program, in which the city bought large plastic garbage cans for many neighborhoods in the city, "a smashing success."

"The fact is that in the last three years there's been a major emphasis, major efforts on basic city services," Barry said. "We are paving more streets in 1982 than ever before, and we are going to pave more in 1983. We've fixed more potholes in the last six months than have been fixed in the last six years."

Barry said his administration has good relations with Capitol Hill, even though a key House subcommittee recently held up the city's federal payment because Barry had not acted on its request to hire more police officers. He implied that such delays are only temporary and to be expected.

"This is the Democratic process," he said, adding later that he was optimistic the city would win in the end