Former West German chancellor Willy Brandt called yesterday for President Reagan and Soviet leader Mikhail Gorbachev to agree in principle next week to ban space weapons and stop deployment of new offensive nuclear weapons.

Brandt, in an address here accepting the $50,000 Albert Einstein Peace Prize awarded by a private foundation, said Reagan and Gorbachev should break the stalemate in arms control negotiations "with the kind of response the world expects of them."

The author of the West German policy of reconciliation with the East that led the way to the 1970's U.S.-Soviet era of detente, Brandt said, "The world needs a second wave of detente and cooperation."

Brandt, who is chairman of West Germany's opposition Social Democratic Party, cautioned against "excessive expectations" for next week's Reagan-Gorbachev summit because the starting positions of the two nations are so different.

The world does not expect Reagan or Gorbachev to convince the other of his ideological view, Brandt said. The world wants them to "establish security and give the assurance that there will be no third world war."

In an interview, Brandt said he believes it "would be enough" for Western Europeans to consider the summit meeting successful if a new program of dialogue between the U.S. and Soviet Union is established.

Brandt predicted that Gorbachev will have no difficulty keeping up his side of the discussion, recalling that Gorbachev referred only to notes on a single, small slip of paper when covering a wide range of questions with Brandt in the Kremlin last May.

In his address yesterday, Brandt proposed five points for basic agreement next week by Reagan and Gorbachev that he said could lead to improved East-West relations and ease world tensions:

*Agreement on regular meetings in the future.

*Fifty percent cuts in nuclear arsenals, including strategic, intermediate-range and short-range weapons.

*A ban on space weapons.

*Immediate resumption of negotiations on a comprehensive nuclear test ban.

*A halt to deployment of new offensive nuclear weapons and a freeze on nuclear explosions and on the development, testing, production, deployment and use of all space weapons including antisatellite weapons.

Several of these ideas have been proposed by the Soviet Union but rejected by the United States in recent months. Asked about this, Brandt said, "A position is not necessarily wrong if brought forward by the Soviet Union."

He added that he had carefully not called for a halt to space weapons research because he believes, as does the U.S. administration, that it is "unrealistic" to ban research.