President Carter's "austere" budget for fiscal 1980 may represent a one-shot effort to cut federal spending rather than the start of a genuine shift away from big government, according to a Brookings Institution study released yesterday.

The study, based on a detailed analysis of Carter's budget proposals, concluded that the austerity "looks like a one-time effort" because so many of Carter's reductions involve savings only for one year.

"The budget hints at, but does not engage in a basic debate about the domestic role of the federal government," the report said.

Meanwhile, the director of the institution's economic study, Joseph A. Pechman, urged Carter not to propose another big tax cut if the economy falls into a mild recession late this year, despite all the economic and election-year pressures.

In a press conference held to discuss the budget study, Pechman said the budget situation now is so tight there is little room for extra economic stimulus measures unless the recession deepens to serious proportions. He called for "steady-as-you-go policies."

The critique of Carter's budget was contained in the latest edition of "Setting National Priorities," the institution's annual analysis of the administration's spending and tax policy plans. The fiscal 1980 volume, which runs 229 pages, is the ninth in the series.

On other topics, the study concluded:

Because of the virulence of the current inflation, Carter's flagging wage-price guidelines program "could be blown apart" by a food-fuel price explosion.

There still is a scant possibility that Carter may reach his goal of balancing the budget by fiscal 1981, but that most likely will be sidetracked by the coming recession, which pechman and other Brookings economists agreed is almost certain.

Even with Carter's austerity policies, the administration will not have enough room in the budget between now and 1984 to cut federal income taxes, roll back Social Security payroll taxes and begin large new spending programs, as many liberals want.

Current efforts to pass a constitutional amendment requiring a balanced budget would put the government "in a stratjacket."

Brookings' concern over Carter's budget was that by seeking modest cuts across the board, rather than concentrating on eliminating large, unneeded program, Carter may have missed the chance to make a permanent impact in reordering his priorties.

Nevertheless, Pechman conceded during the press conference that the piecemeal approach the president has tried may be the only way to get Congress to go along with budget cuts.

A House-Senate conference committee last week agreed on a set of compromise fiscal 1980 congressional budget targets that essentially paraleled Carter's January recommendations, but called for a deficit of $23 billion - $6 billion below the president's.

Pechman said that ironically one thing that may help Carter get closer to his balanced budget goal is that inflation is so rapid that the government most likely will take in more tax revenues than expected, helping to trim the size of the deficit further.