In his latest bid to show District of Columbia taxpayers that he can provide them with more tax relief than his mayoral opponents, City Council member Marion Barry (D-At Large) yesterday endorsed a wide range of city tax law changes proposed last December by a citizens advisory panel.

Berry, chairman of the City Council's finance and revenue committee also immediately tried to put the burden of cooperation in enacting any tax changes on his two chief foes in the Sep. 12 Democratic mayoral primary, City Council Chairman Sterling Tucker and Mayor Walter E. Washington.

Barry asked the mayor, who is expected to run for another four-year term but has nto formally announced his candidacy, to appoint a staff member to work with one of Barry's committee staff members on the tax proposals and urged Tucker to support the hiring of tax experts on a temporary basis to help draft the necessary legislation.

"With the additional staff that you provide," Barry said in a letter to the mayor, "District taxpayers will have substantial tax reform this year."

A spokesman for the mayor said he had not read the letter, but had directed city finance director Kenneth Back to study the 68 tax changes proposed by the D.C. Tax Revision Commission. The spokesman said the mayor supports most of the revisions, but opposes taxing churchowned property, as Barry also did yesterday.

Tucker is in Colorado attending a meeting of regional governmental councils and was not available for comment.

Barry said his mayoral primary opponents could ignore his requests for help in enacting the tax changes, "but I don't know why.It benefits the city."

For the last three months, Barry, Tucker and Washington have made a variety of tax proposals, each of them apparently attempting to upstage the other and catch the voter's eye. Tucker has estimated thant his proposals would benefit taxpayers by $5.5 million, while Barry says his will help taxpayers by $15.3 million. The mayor says his would save taxpayers $13.9 million.

Barry and Washington both favor differing real estate tax rates for commercial and residential property, while Tucker has proposed a system of real estate tax deferrals depanding on a home owner's income.

Along with other proposed changes drafted by the 20-member Tax Revision Commission, Barry said he favors conforming the city's tax forms to those used by the Internal Revenue Service for federal income tax returns. He would also replace the $750 tax exemption now granted District taxpayers with a $35 tax credit to benefit more low and moderate-income residents, enact an unspecified "minimum" income tax so that everyone pays some income tax and remove the real estate tax exemptions that some trade associations and professional groups now enjoy.

However, Barry said that unlike the commission, he opposes taxing churhces and universities and broadening the city's 5 percent sales tax to include such small businesses as cleaning establishments and barbershops.

In addition, Barry said he favors the continued taxing of commercial and business buildings at the current real estate tax rate of $1.83 per $100 of assessed valuation, while taxing private residences at a $1.57 rate, a provision the commission opposed.

Barry said real estate owned by churches and universities should not be taxed because they provide a variety of services to the city's residents. Any additional taxes on services provided by small businesses would only hurt people who often already are financially hard pressed, he said.