Congressional negotiators yesterday dropped a Senate demand that would have placed restrictions on the sale of U.S. nuclear technology to China under a trouble-plagued agreement that took effect last week.

In a related move, President Reagan signed a congressional compromise resolution that supports peaceful nuclear-power cooperation with China but requires additional nonproliferation assurances.

The Senate language to block nuclear shipments to China until that nation adopts international standards for safeguarding nuclear material was attached to a catchall spending bill under debate. The amendment, offered by Sens. John Glenn (D-Ohio) and William S. Cohen (R-Maine), passed last week by a 59-to-28 vote.

But the conference voted 15 to 7 yesterday not to accept the amendment after White House and State Department officials warned it would seriously damage U.S.-China relations and might lead to a presidential veto of the entire omnibus spending bill.

Reagan then signed the resolution, which had been on his desk but had been held up pending action on the Glenn-Cohen amendment.

"I strongly object to that amendment," Reagan said in a statement drafted before the vote.

Under the resolution, Reagan will certify to Congress that he has made "effective" arrangements with the Chinese to ensure "that nuclear exports . . . are used solely for intended peaceful purposes" and that China no longer assists other nations who aspire to join the club of nuclear-weapons states.

In deference to the Senate critics of the pact, which Reagan first initialed 20 months ago in Peking, the president said the agreement "will lead to a continuing dialogue with China on important nuclear energy and non-proliferation matters."

Both Glenn and Cohen have said that they will attempt next year to attach greater restrictions on nuclear exports to China.