The Senate yesterday put Congress on a collision course with President Reagan on arms control by voting to compel him to comply with weapons limits in the SALT II agreement as part of a defense bill for this fiscal year that also would curb development of his Strategic Defense Initiative.

The $303 billion military authorization bill was passed on a virtually party-line vote of 56 to 42 after the Democratic-controlled Senate voted, 57 to 41, to stop Reagan from exceeding nuclear-launcher limits prescribed by the unratified 1979 SALT II pact with the Soviets.

The bill now goes to a conference with the House, which has approved these and other arms constraints, including a proposed ban on nuclear testing that was rejected by the Senate.

Reagan responded to the Senate action by renewing threats to veto the measure, and yesterday's roll calls indicated that Democratic leaders would be unable to muster the two-thirds vote of both houses that is necessary to override a veto.

But senior Senate Democrats warned that Congress will keep sending the arms proposals back to the White House in bills required to fund the Pentagon for fiscal 1988, which started Thursday. "Sooner or later he's going to have to sign a bill that pays for the men and women who defend this country," Majority Leader Robert C. Byrd (D-W.Va.) said.

"These issues are not going to fade away with a veto," Senate Armed Services Committee Chairman Sam Nunn (D-Ga.) said. Nunn's support of both provisions after a long history of opposing such constraints mirrored the change that has come over the Senate as a whole on arms control.

While the House has repeatedly passed stiff arms constraints, the Senate had refused until this year. The combination of mounting opposition to some of Reagan's arms plans and Democratic control of the Senate produced a challenge of unprecedented proportions to the president's arms policy.

"What we have here is a Democratic Congress on a direct collision course with the president of the United States," Sen. Dan Quayle (R-Ind.) said.

Byrd put it another way: "Sooner or later there has to be a grappling with reality. . . and the sooner the White House understands it the better."

The defense bill passed after Democrats abandoned efforts to include provisions to require congressional approval for long-term continuation of the administration's controversial tanker-escort operation in the Persian Gulf.

The Senate Thursday shut off debate on imposing war-powers curbs on the gulf operation by a vote of 54 to 45, six short of the number necessary for cloture, posing a threat of an indefinite filibuster of the defense bill.

Although separate legislation to impose the war-powers constraints can be brought up next week, it would be vulnerable to filibuster. Sen. Lowell P. Weicker Jr. (R-Conn.) appeared pessimistic about prospects for action and castigated Congress as well as Reagan for failing to invoke the Vietnam-era War Powers Resolution.

"What kind of body count will there have to be before we vote. . . ?" asked Weicker, charging that both the war-powers law and the Constitution were "missing in action. . . unreported casualties" of the U.S. involvement in the gulf war.

While abandonment of the war-powers provisions gave Reagan a reprieve on that issue, the SALT II and Strategic Defense Initiative (SDI) provisions were enough to prompt new veto threats and condemnation from Reagan, who said they would "undercut my efforts to negotiate equitable and verifiable arms reductions and undermine national security."

The SALT II provision would require the administration to comply with limits for multiple-warhead ballistic missiles and bombers as prescribed by the treaty and observed by the United States until late last year, when the ceilings were breached. The limits would apply only if the Soviets also observed them.

The SDI provision would require congressional approval for testing and development of an antimissile defenses in space that violates the traditional narrow interpretation of the 1972 Antiballistic Missile (ABM) Treaty.

The SDI testing curbs were approved, 58 to 38, two weeks ago after the Senate finally broke a four-month impasse on the issue, paving the way for completion of the defense bill after deliberations that included 120 hours of debate, consideration of 118 amendments and 42 roll-call votes.

In his statement, Reagan said a "Sooner or later there has to be a grappling with reality. . . and the sooner the White House understands the better."

-- Sen. Robert C. Byrd (D-W.Va.)

broader definition of the ABM Treaty that would allow expanded SDI testing is "fully justified" and would "enable us to save time and money in developing effective defenses against a potential Soviet missile attack."

Referring to both provisions, he said the Senate actions would "undermine our negotiators in Geneva at a particularly crucial time" and were "particularly ironic" in view of Soviet missile tests earlier this week near Hawaii, which drew sharp protests from the U.S. government.

In voting to force compliance with the SALT II weapons limits, the Senate attempted to make a distinction between imposing numerical limits on weapons and legislating enactment of treaty provisions.

It unanimously approved Republican-proposed language asserting that the United States is not obligated to abide by the treaty unless certain conditions are met, such as ratification of the treaty. But the numerical limits on missile launchers remained in the legislation.

"Some days we live by the spirit of the law. Some days we live by the letter of the law. Some days we do both, but not often," Nunn observed.

If the move was aimed at undermining the push for weapons limits prescribed by the treaty, it appeared to have the opposite effect. Nunn, who voted Thursday to table the SALT II restraints, switched to support the weapons curbs yesterday, saying the disclaimer about legislating treaty provisions "cured the problem" as far as he was concerned.

But approval of the Republican language did little to win GOP support for the bill on final passage. It was an unusually partisan vote for a defense authorization bill. Only Republicans John H. Chafee (R.I.), William S. Cohen (Maine), John Heinz (Pa.) and Robert T. Stafford (Vt.) voted for it. Only Democrats William Proxmire (Wis.) and Ernest F. Hollings (S.C.) voted against it.

The vote for the SALT II weapons limitation was more bipartisan, with eight Republicans supporting and five Democrats opposing. Maryland's Democratic senators supported the limitation; Virginia's Republican senators opposed it.

The Senate's defense bill authorizes $14 billion more for the Pentagon than the House's $289 billion version, although it represents a substantial reduction from Reagan's request of $312 billion.

The Senate bill would increase spending only enough to cover the cost of inflation and is subject to further cuts to meet congressional budget targets.

It would cut Reagan's SDI request from $5.7 billion to $4.5 billion, compared with $3.1 billion approved by the House. Both bills call for two new aircraft carriers and a pay increase for military personnel: 4 percent in the Senate bill, 3 percent in the House bill. Both also grant many, although not all, of the administration's requests for ships, tanks, planes and missiles.

The Senate measure also calls for an embargo on imports from Iran and scrapping of the U.S.-Soviet embassy agreement to require relocation of the new Soviet embassy compound on Mount Alto to lower ground in Washington.