While vacationing in California last summer, President Reagan was described by senior White House officials as poised to launch a confrontational "veto strategy" against Congress. But the record of the last few months shows that he decided instead to continue negotiating rather than to fight with Capitol Hill.

For all of his threats about wielding a veto pen, the president has used it sparingly in the intensive period since Labor Day, blocking a trade bill and an appropriations measure.

Other veto targets set by the White House last summer, such as the farm and appropriations bills, were negotiated to Reagan's satisfaction. A veto threat was made yesterday against the budget-cutting measure being considered in the final hours of this congressional session.

Despite calls from some conservatives for more active use of the veto, Reagan has set a pattern of using it as a threat, then negotiating a compromise. He has issued fewer vetoes, on average, than other presidents of this century, according to a study last July by the conservative Heritage Foundation.

The approach of conciliation rather than confrontation was often employed by former Office of Management and Budget director David A. Stockman and continued this fall by the new White House team under chief of staff Donald T. Regan, even though the Regan group brandished the "veto strategy" last summer.

"The veto strategy was taken seriously enough that Congress brought domestic appropriations bills within the guidelines, their own budget resolution," OMB spokesman Edwin L. Dale Jr. said.

The budget resolution, as he and others noted, included more domestic spending and less for defense than Reagan originally sought.

Reagan identified the farm bill as a possible veto target in a radio address Aug. 17, insisting that Congress stick by its $34 billion budget goal for the legislation. Aides predicted confidently then that a "budget-busting" farm bill would be a prime veto target.

But, through more realistic crop assumptions and other changes, the price of farm legislation escalated, and the White House set a new $50 billion bottom line as Congress neared the end of the session. This week, Reagan agreed to sign next Monday a $52 billion farm bill that includes improvements he had sought, such as price-support reductions.

Aside from its cost, the farm bill includes sugar, milk and export provisions that White House officials describe as seriously objectionable.

Upon its passage this week, some presidential aides urged a veto. But others said a veto probably would not result in improvements by Congress, and Reagan was persuaded instead to seek changes next year.

"This is vintage Reagan. You get two-thirds of what you want and then ask, 'Can we fight another day on the rest?' " a White House official said.

The official noted that Reagan signed a catchall spending bill Thursday night despite a provision banning further tests of antisatellite weapons in space. Although the administration objected to the testing ban, "there were a lot of other good things in the bill" and Reagan decided to sign it, the official said.

The trade legislation, which would have sharply limited imports of textiles, shoes and copper, offered a different example. Reagan had made a concerted effort since Labor Day to head off protectionist pressure in Congress with administrative action seeking more open markets for U.S. goods and with a Treasury Department move to lower the value of the dollar gradually.

As a result, support for the trade bill decreased to the point that Reagan's veto could not be overridden immediately.

Last summer, Reagan also seemed to be heading for collision with Congress on sanctions against South Africa, but he compromised, averting confrontation by agreeing to limited sanctions.

"I thought we would see a lot more vetoes this year," said James Gattuso, a policy analyst at the Heritage Foundation who wrote a study last summer urging Reagan to use the veto as his "trump card" against Congress.

"The problem," he wrote then, "is that . . . Reagan actually has been very timid in playing this trump card thus far in his presidency. This apparent aversion to vetoing may seriously impair Reagan's ability to prod Congress to act responsibly, particularly in slashing federal spending -- where few major victories have been won since 1981."

Gattuso calculated that, in his first term, Reagan used the veto on average 10 times a year, compared with an average of 18 times a year for his predecessors in this century. For example, President Jimmy Carter averaged only eight vetoes a year, Gerald R. Ford 22 and Richard M. Nixon eight.

Yesterday, Gattuso attributed the low number of vetoes this fall to institutional pressures at the end of the congressional session.

"All the advisers are saying Congress won't be able" to reconvene to modify vetoed legislation. "It would cause chaos . . . . There seemed to be a feeling you can't veto at the end of the year. That's something the White House knew would be happening all along. They should have been prepared for that."