Assisted by last-minute lobbying from Vice President Bush and industry, the first U.S. nuclear-power cooperation agreement with a major communist nation -- China -- is expected to clear its final congressional hurdle before the Christmas recess.

Still unresolved is an amendment to a continuing budget resolution being considered by House and Senate conferees. It was offered by Sens. John Glenn (D-Ohio) and William S. Cohen (R-Maine), both critics of the nuclear pact, which took effect last week.

The amendment requires that any nuclear technology sold to China meet the same standard for safeguarding nuclear material as is met in all other U.S. nuclear agreements. The Senate approved it, 59 to 28, and Glenn and Cohen say that, if the conferees reject it, they will return next year with new legislation.

The amendment went beyond a compromise resolution adopted by both chambers requiring that, before any nuclear technology leaves the United States, the president must certify to Congress that China has clarified its nonproliferation policies.

"I never, in the 11 years I have been here, have seen the administration put on such a full-court press for reasons I don't quite understand," Glenn said wearily Friday.

He had just learned that White House officials were expressing confidence that they had gained enough votes among Republican conference members to block the amendment this week.

"They're about to cave," echoed Cohen, referring to Republicans who had supported the amendment on the Senate floor but switched votes in the face of intense White House and State Department pressure.

According to both senators, the pressure included a specific threat that President Reagan would veto the entire stopgap spending bill if the China nuclear agreement was encumbered by further restrictions.

Glenn and Cohen said they spoke with Bush Friday. "He said they don't want to see this forced into renegotiation and they just felt the Chinese would dump the whole thing," Glenn said.

The agreement allows U.S. nuclear supply corporations, such as Westinghouse and General Electric, to bid on contracts to supply equipment for China's ambitious nuclear-powered electrification program.

Stuart E. Eizenstat, a senior White House aide under President Jimmy Carter, represented Westinghouse and other nuclear suppliers in last week's lobbying effort.

"I think this was really the best deal they could get," Eizenstat said, referring to U.S. negotiators.

The industry view, he added, is that the administration had tried for two years to obtain stronger commitments in writing from China that it would not assist other nations to acquire nuclear weapons and would adhere to strict international safeguards on all technology provided by U.S. suppliers.

"If they were not able to get a stronger commitment up to this point, it was not likely that they would get it subsequently," he said.

The controversy over the China accord involves those who see it as a natural extension of the strategically important U.S.-China relationship and a new market for the ailing U.S. nuclear industry and those concerned that China may continue assisting and encouraging Third World nations to acquire nuclear weapons.

The accord has been criticized as lacking clear language guaranteeing that shipments of nuclear material to China would not be diverted to nations aspiring to build atomic weapons.

The administration has vigorously defended the agreement, noting that during more than two years of negotiations, China has for the first time renounced the spread of nuclear weapons and has joined the International Atomic Energy Agency. The IAEA is dedicated to worldwide supervision and control of nuclear material.