President Reagan's top advisers have mapped out a strategy for the next few months that envisions a more confrontational approach to Congress over federal spending, trade, taxes and farm policy, administration officials said today.

The short-term strategy, still being refined, suggests that Reagan may be steering away from political accommodation and more toward open combat to achieve his domestic policy goals.

"Every poll shows that the American people want federal spending curbed and deficits reduced," White House chief of staff Donald T. Regan said today in an interview, describing the president's goals in the next few months. Regan has been reporting to the president daily on planning for fall political strategy, a senior official said.

Several top Reagan aides who asked not to be identified said the president can be expected to use his veto powers more than he has in the past in an attempt to hold down spending, fend off tax increases and quell the demand for trade protection.

But officials also stressed that Reagan would attempt to bring Congress -- particularly Republicans -- around to his point of view before challenging the lawmakers on specific items. They also said the president would make his stand on a few highly symbolic points rather than wage a broad confrontation with Congress.

The pressures on trade, taxes and spending are expected to confront the president this fall after a summer that has seen fresh discord between Reagan and his Republican congressional allies and legislative setbacks for the White House.

The new approach, eight months into Reagan's second term, carries some political risk. It could generate a new cloud of disharmony with Congress and alienate Democrats the president needs if his bipartisan effort to rewrite the tax laws is to succeed.

But top White House officials said they believe the risks are worth bearing. "The risks are already there," another senior White House official said. "We can't crawl under a table" and ignore them, he added.

The officials said they share a renewed concern that the 34-month economic recovery may be running out of steam. They said a more confrontational approach is therefore necessary to hold down spending, prevent tax increases and head off restrictive trade measures -- all of which they said threaten the recovery.

But the new approach also reflects the dramatically different style that chief of staff Regan has brought to the White House. In recent months, Regan has demonstrated an instinct for a more direct and sometimes confrontational approach to Congress compared to his predecessor, James A. Baker III, now Treasury secretary. Baker earned a reputation as a legislative tactician who often sought to negotiate with adversaries rather than fight them.

This week, for example, Regan directed aides to begin laying the groundwork for a possible autumn veto confrontation with Congress over spending bills. "We've laid down a marker here," a senior White House official declared.

By contrast, in the first term, Baker often had spending bills negotiated to White House satisfaction by David A. Stockman, who recently resigned as director of the Office of Management and Budget.

"Stockman was always the type who wanted to deal, and Baker let him," said the senior official. "He went up on the Hill and who the hell knew what they were doing, and as a result this was how policy got set.

"Because Stockman didn't like bridge-building, we didn't get bridge-building. Stockman likedsewer-building, and we got sewer-building. That's not my idea of the way to do it."

One area where the new White House approach is already at work is the farm bill. A group of administration officials is searching for ways to further hold down the cost of legislation pending in the House and Senate agriculture committees. "If Congress busts the budget -- and it's quite obvious -- we know we're going to be over on the farm program," the senior White House official said.

"We have corn coming out of everywhere," he said, noting forecasts of huge crops of soybeans, wheat and cotton as well. "With all of that, it's really going to be expensive," he said. This will require deeper budget cuts in other areas, he added, to hold the line on the federal deficit.

"We're going to try to get this point across to the American people," the official said. "We're not vetoing for the sake of political philosophy or the fact we want to be confrontational. We're vetoing in order to protect the economy."

On trade issues, Reagan faces a growing demand for protection against imports. The senior official said the administration hopes to have a trade policy ready by mid-September that will resist protectionism "as much as possible" but will "go after dumping" of foreign goods on U.S. markets.

On taxes, officials said Reagan is determined to withstand pressure for an increase. They acknowledged that an effort may be made to raise revenue as part of the overall revision of the tax code this fall. "We don't want tax reform at any price," one official said.

On federal spending, Reagan has served notice that he will veto "excessive" appropriations bills. But the senior White House official said Reagan would be selective, choosing his fights with Congress carefully.

The president was scheduled to meet at his ranch near here late today with Vice President Bush to go over the recent strategy discussions.

Leading Senate Republicans have been at odds over fiscal policy with Reagan this year, but the senior official said GOP members seeking reelection in 1986 "should be on our side" because polls show public support for cutting deficits and against tax increases. "This is what their constituents want," he added.