TEHRAN, Iran--Shah Mohammed Reza Pahlavi yesterday accepted the advice of Shahpour Bakhtiar, whom he appointed prime minister last week, to "rest and take a vacation" while Bakhtiar tries to form a civilian cabinet to replace the military government and quell the violent protests against the Shah.

The Shah left Tehran yesterday for a two-day vacation in Jajroud, a ski resort approximately 40 miles east of the capital city.

Meanwhile, Ayatollah Khomeini, the Shah's leading opponent, said yesterday the Shah and his family should be imprisoned for life. "That would be the minimum, and also the return of all the property that he has confiscated from the people. The Shah and his immediate family are criminals and they have to be tried and punished according to Islamic laws," said Khomeini.

Khomeini, the spiritual leader of the dissident Iranian Shiite Moslems, was exiled from Iran by Pahlavi in 1963 after the outbreak of protests against the Shah's modernization program. He now lives in Paris.

The exodus of Americans and other foreigners from Iran continued yesterday, although the level of violence tapered off drastically. There were no reports of clashes anywhere in the country yesterday.

Nevertheless, a U.S. embassy spokesman said yesterday about 4000 Americans are expected to leave Iran in the next few days and that the total number of Americans in the country will drop to 25,000 from the 45,000 in Iran before the violent riots erupted three months ago.

State Department spokesmen said yesterday an American envoy had again complained to the Soviet foreign ministry in Moscow that Soviet propaganda broadcasts into Iran are "unhelpful."

The Soviet newspaper Izvestia yesterday charged that the appointment of Bakhtiar as prime minister, regarded by many as a pro-West moderate, was the result of U.S. "political machinations" designed to safeguard American interests in Iran.