The director of President Reagan's Strategic Defense Initiative (SDI) research program said yesterday that it will be at least 10 years before the United States can begin deploying a missile defense system, if research proves that such a system is feasible.

Lt. Gen. James A. Abrahamson said deployment could start only "after the mid-1990s" and only if by 1992 the president and Congress decide to proceed with development.

Abrahamson's remarks, made on the CBS News program "Nightwatch," came as the Reagan administration considers a Soviet proposal to link continued U.S. adherence to the 1972 Antiballistic Missile (ABM) treaty for 15 to 20 years to deep cuts in strategic nuclear weapons.

Reagan has tentatively decided to tell Soviet leader Mikhail Gorbachev that he will discuss the Soviet suggestion on deployment of a future defensive system as part of his response to Moscow's recent arms proposals, according to administration sources. A letter to Gorbachev is being drafted by the White House and consultations are underway with U.S. allies in Europe and Asia.

In Bonn yesterday, a West German official said his government would like Reagan to offer Gorbachev "a workable compromise" on space defense, Washington Post correspondent Robert J. McCartney reported.

West German Foreign Minister Hans-Dietrich Genscher planned to make that point in a meeting here with Secretary of State George P. Shultz, according to West German sources. Genscher was scheduled to spend three hours in Washington last night to give his government's formal response to Reagan's ideas and brief Shultz on his conversations this week in Moscow with Gorbachev and Soviet Foreign Minister Eduard Shevardnadze.

Some key administration arms control experts, primarily in the State Department, have said the United States could counterpropose continued adherence to the treaty for five or six years without harming the SDI research program, according to informed sources.

One way to do that, sources said, would be to have both superpowers agree not to seek modifications in the ABM treaty when the regular five-year-review meeting on the agreement takes place next year. The two leaders could also agree that their nations would abide by the treaty until the next review session takes place in 1992.

Under the treaty's language, either side can now withdraw from the pact with six months' notice.

Abrahamson refused to give his view of an agreement to continue to adhere to the treaty's terms, saying "that is a decision for the president to make." But he noted that it was an "interesting trade" as long as "we procede with the research phase" and then make the political decision whether or not to go ahead with development and deployment.

He added that reductions in nuclear weapons would "make it easier for strategic defense."

Abrahamson also pointed out that the Soviets also have an active program of missile defense research and may be capable of "breaking out" of the treaty more quickly than the United States. An agreement to continue adhering to the treaty, he said, would also be applicable to the Soviets and prevent them from deploying a missile defense system.

He warned that the Soviet proposal also sought to add definitions for the ABM treaty which could "limit and control SDI research." It is "important that we lay out for the administration what restrictions would be harmful and what would not," Abrahamson said.

The decision to move from SDI research to development of specific space defense weapons, Abrahamson said, may be delayed beyond 1992 if Congress sharply cuts the SDI budget for next year to $3.5 billion. That figure, which is $1.3 billion below the president's request, is the amount likely to be finally approved by Congress, according to Capitol Hill sources.

SDI research, Abrahamson said, was "deliberately designed" to stay within the treaty limits as now written. If the decision is made to go ahead with an actual system, he said, "development tests will go beyond the treaty."

In a related matter, Ambassador Max M. Kampelman, chief U.S. negotiator at the Geneva arms talks, expressed optimism over current U.S.-Soviet maneuvering in an interview by foreign journalists over the United States Information Agency's Worldnet system.

Kampelman said "there is absolutely no reason why the United States and the Soviet Union in our Geneva talks cannot come to broad agreement on a number, if not all, of the major questions that divide us."