President Carter's special Mideast envoy, Sol M. Linowitz, is preparing to tell the leaders of Egypt and Israel that President-elect Ronald Reagan does not plan to abandon or change the Camp David peace process without their agreement.

Administration sources said yesterday Linowitz will convey that message to Egyptian President Anwar Sadat and Israeli Prime Minister Menachem Begin when he visits the Middle East beginning next Friday.

According to the sources, the decision resulted from talks between Linowitz and Reagan's chief foreign policy adviser, Richard V. Allen. After Linowitz told the Reagan people that there was considerable nervousness in both Egypt and Israel about possible changes in the direction of U.S. policy, Allen authorized him to reassure both leaders that Reagan plans no drastic shifts.

The sources described the move as primarily intended to be reassuring and added it is likely to be several months, perhaps until next spring, before the incoming Reagan administration has thought through its approaches to continuing the drive for an agreement on autonomy for the Palestinian inhabitants of Israeli-occupied Arab territories.

There has been talk among some Reagan advisers about possibly switching to the Jordanian option" -- an idea advocated by Israeli opposition leader Shimon Peres that would attempt to draw Jordan into the peace process. The Pere plan, in broad outline, envisions not an autonomous status for the West Bank and Gaza Strip territories, but a partitioning that would give part of the West Bank to Israel for defensive purposes and reunite the rest with Jordan.

So far, though, Jordan's King Hussein has resisted all efforts to entice him into the Egyptian-Israeli peace negotiations that began at the Camp David summit in 1978.

Although the Camp David accords envision Jordan's eventual participation in the process, the message being carried to the Mideast by Linowitz, the sources said, will stress that nothing will be done by the United States in this regard unless it is agreed to by both Israel and Egypt and is in accordance with their ongoing talks.

Linowitz is known to believe that the autonomy negotiations finally have reached a point where they show signs of making significant progress and is understood to be fearful that the momentum will be lost if the transition from Carter to Reagan causes too long a gap in giving the Mideast priority attention.

Accordingly, the sources said, he has urged Allen and other Reagan advisers to give some urgency to appointing a new Mideast negotiator who is personally close to Reagan and will have the new president's trust. Although it is not yet clear whether Reagan plans to continue the special envoy approach employed by Carter. Allen did agree with Linowitz that a special gesture of reassurance was require;d.

Underscoring Linowitz's point about nervousness in the region was the visit here last week of Egyptian Vice President Hosni Mubarak. He delivered to Carter a message from Sadat stressing the Egyptian leader's concern that the urgency of the Mideast situation not be forgotten in the transition process. It was partially as a result of the Sadat message that Carter decided to send Linowitz on a final trip to the region, the sources said, and when this was communicated to Reagan forces through Allen, they agreed to join in a bipartisan gesture of reassurance.