Mayor Marion Barry yesterday characterized as disastrous and devastating the Wednesday decision by the House District Appropriations subcommittee to reduce the federal government's contribution to the District of Columbia budget to its lowest level in a decade and a half.

"This is a new administration and we are trying to instill a sense of renewed spirit and energy among D.C. citizens for their city and government," Barry said. "Budget cuts of this magnitude tend to undermine our efforts so far."

"The battle's not over yet," Barry said. "We may be down to the 25 count, but we're not out of the fight."

"Certainly there is a need for frugality," Barry said in a lengthy and detailed official response to the preliminary congressional action. "But the federal government would never consider imposing reductions on themselves of the same relative magnitude imposed on D.C. via federal payment reductions."

Barry said he was optimistic that he would still be able to gain congressional approval of a $1.4 billion D.C. operating budget for the fiscal year beginning Oct. 1, including a $317 million U.S. payment.

On Wednesday, the subcommittee recommended a federal payment of $191.5 million, $125.5 million less than requested by Barry and the City Council and recommended by the White House. The subcommittee recommended reducing the operating budget to $1.35 million, $78 million less than the city had sought.

As recommended by the subcommittee, the FY 1980 federal payment would make up 14.2 percent of the city's budget, the lowest federal share since 1965. In actual money, the 1980 figure proposed by the panel would be the smallest federal payment since 1974.

The federal payment is the annual allocation given to the city to compensate for the loss of revenues from tax exempt properties and the unique municipal financial burdens associated with being the nation's capital.

A senior official in the Barry administration, who asked not to be named, attributed the cuts to a conservative philosophy and a lack of understanding of the city's problems on the part of the subcommittee chairman, Rep. Charles Wilson (D-Texas).

"Philosphically, Charles Wilson . . . is a conservative, and his conservatism showed itself in how he approached the budget," the official said, adding that Wilson had reduced social services spending but not cut back allocations for police and fire services.