The U.S. and Soviet Olympic committees will sign on Sunday an accord providing for exchanges of athletes, coaches and training camp visits over the next three years leading up to the 1988 Summer Games in Seoul.

U.S. Olympic spokesman Mike Moran said, "We hope it will establish a climate that will lead to a return of Olympic participation" by the Soviets, although the agreement contains no such Soviet commitment.

The Soviets declined to particpate in the 1984 Olympic Games held in Los Angeles. The United States boycotted the 1980 Summer Olympics in Moscow because of the Soviet invasion of Afghanistan.

Moran said informal indications about Soviet participation in the 1988 Games are positive. State Department officials agreed, but said a definite Soviet decision is unlikely until much nearer the event, which could be complicated by the continuing confrontation of U.S. ally South Korea, where the Games are to be held, with Soviet ally North Korea.

Marat Gramov, head of the Soviet National Olympic Committee, is to sign the accord with U.S. Olympic Committee President Robert H. Helmick in a colorful ceremony at Indianapolis in the presence of International Olympic Committee President Juan Antonio Samaranch.

Indianapolis was chosen for the event because it is the site of the 1987 Pan American Games, one of the major international sporting events leading up to the 1988 Olympics.

An official of the Indianapolis committee said he hoped the Soviet presence in Indianapolis and the U.S.-Soviet sporting accord would encourage Cuba to participate in the Pan-American Games.

Because only teams from this hemisphere are eligible, Soviet athletes will not be involved in the Indianapolis Games.

The accord to be signed Sunday contains, among other things, authorization for reciprocal visits to the training sites in the two countries for Olympic athletes and exchange of sports medicine personnel and information.

Soviet athletes, coaches and officials are expected to visit the three U.S. camps at Lake Placid, N.Y., Colorado Springs and Marquette, Mich. The Soviets are reported to have a large number of such camps and an extensive athlete preparation program.

Moran said U.S. and Soviet athletes whose exchange would be fostered by the new accord would probably put on exhibition matches during their visits to the other country.