D.C. City Council member John Ray, a Democratic candidate for mayor, has proposed reducing the city's business tax rates to encourage small businesses to remain in Washington instead of seeking a more favorable climate in Virginia and Maryland.

However, Ray said yesterday that he probably will not specify where he would make the tax cuts during the campaign. Instead, he said, he would wait until after the election to establish a study commission to advise him on how best to proceed--assuming, of course, that he wins election.

"I can't give you a laundry list now of what all those taxes will be," Ray said. "I'm not sure I've got all the resources to do that . . . But if I'm elected mayor, I will get rid of a lot of the taxes that are driving businesses away."

Ray's reluctance to be more specific drew fire yesterday from Mayor Marion Barry, who said Ray has had three years on the council to come up with proposals for providing local businessmen with added incentives.

"If he's got a good idea, then he should bring it forth," Barry said in a telephone interview. "Instead of all of this rhetoric, let's have some performance."

In a speech Friday to an organization of Washington lawyers and corporate executives, Ray said the city "may well have to get rid of some taxes which are producing short-term revenue growth for us" in order to keep small businesses in the city and attract new businesses.

Ray predicted that the long-term benefits to the city of a reduction in business taxes and professional fees would more than offset the short-term negative impact it would have on the city's treasury.

In recent months, city tax revenues have run far ahead of the Barry administration's projections. Last year, revenues grew by 10 percent without any substantial increases in the taxing authority. This unexpected growth helped to produce a $68 million surplus for fiscal 1981 that helped substantially to reduce the city's accumulated deficit.

"We may not see that rate of growth in revenues for the next four or five or maybe six years if we carry out the kind of tax reform program and other incentives we need to hold on to some of these businesses," Ray said.

Although Ray has offered few specifics in his proposal, his press secretary said yesterday that his search for places to cut would focus on the income and franchise tax on businesses, professional licenses and fees, the gasoline tax and the unemployment compensation tax on businesses.

Ray, a one-term, at-large council member who last January became the first one to formally challenge Barry for nomination as mayor in the Sept. 14 Democratic primary, plans to release a major policy statement next week, outlining what he considers the major issues in the campaign.

The statement will summarize his views on the need for improved city management, economic development, crime prevention, jobs programs, and health and human services, according to Margaret Gentry, Ray's press secretary.

Until now, Ray and his campaign aides have spent most of their time raising funds, organizing volunteers and attempting to increase Ray's name identification among voters through a series of radio commercials and advertising on the sides of Metro buses.

In the second phase of his campaign, Ray said, he plans to develop his platform by issuing a series of position papers.