Two Harvard professors were among six experts on Soviet affairs who briefed President Reagan yesterday afternoon in preparation for his upcoming meeting with Soviet leader Mikhail S. Gorbachev.

Adam B. Ulam, Gurney Professor of History and Political Science and director of the Russian Research Center, and Richard Pipes, Baird Professor of History, attended the luncheon meeting.

The briefing was designed to bring together "a number of leading experts in different areas" to inform the President about "a broad range of issues relate to Soviet relations," according to White House spokesman Michael Guest.

All-Star Lineup

The other experts attending the meeting included both those with background in government and academics. Also present at the briefing were Secretary of State George P. Shultz, Secretary of Defense Caspar W. Weinberger '38, Vice President George Bush, and several national security advisors and other members of the administration, Pipes said in a telephone interview from Washington.

The summit, which will take place on November 19 and 20 in Geneva, will mark the first meeting between Reagan and Gorbachev.

Ulam, author of 11 books on the Soviet Union, is a prominent Sovietologist and a "leading historian on Soviet foreign policy," Guest said. Although Ulam has done advisory work in Washington several times, he had never met with Reagan, Ulam's wife said yesterday.

Ulam recently returned from a visit to the Soviet Union at the request of the American ambassador, where he gave lectures and met with academians and historians, his wife said.

Pipes served in the Reagan Administration on the National Security Council as Director of East European and Soviet Affairs in 1981-1982, and has frequently briefed the President in the past, he said yesterday. Although he left the administration in December 1982, Pipes said that he has returned to Washington many times, serving in an advisory capacity.

Marshall Goldman, associate director of the Russian Research Center, said he was not surprised that Ulam and Pipes were among those invited to the meeting. He called them "two of the best-known specialists in the country. If I were the President, I'd invite them, too."

The group discussed "the Soviet experts' view of the Soviet Union, the current status there, some recommendations on how the President can present his views, what the expected responses are, what the Soviet mentality is in dealing with U.S.-Soviet relations, et cetera," presidential spokesman Larry Speakes said at a press conference yesterday.

"Each of us tried to explain what Soviet strengths and weaknesses are, what the president can expect in Geneva," Pipes said.

Pipes said that in his experience as a presidential advisor he had never attended a session like yesterday's. He termed the format of the meeting "very unusual," describing it as "almost a seminar."

The experts who were present respesented a variety of viewpoints on Soviet issues, Pipes said. "The agreement among these people was not very wide," he said, adding that there was a "spectrum of opinion, but nothing violent."

Pipes said that he doubted yesterday's briefing would significantly alter the President's views on Soviet affairs, stressing that this was only one of many sessions the President would attend in preparation for the summit.

"I wouldn't exaggerate the importance of the advising session," he said. "I don't think such a meeting will change his mind about anything.