President Reagan wrote Soviet leader Mikhail Gorbachev last week proposing a meeting soon between Secretary of State George P. Shultz and Soviet Foreign Minister Eduard Shevardnadze to plan the next superpower summit, White House officials said yesterday.

The letter, described as "conciliatory" in tone, was delivered by U.S. Ambassador Arthur Hartman, the officials said.

The president's proposal to restart the planning for a summit meeting with Gorbachev came as he was defending his May 27 decision to abandon the limits of the unratified SALT II strategic arms agreement because of alleged Soviet violations. That decision has drawn criticism from the Soviets, U.S. allies and members of Congress.

The letter to Gorbachev also apparently coincided with a new Soviet proposal on reducing strategic weapons, placed on the negotiating table in Geneva Wednesday.

U.S. officials have differences of opinion over the seriousness of the latest Soviet proposal, but unlike previous offers from Moscow, the administration has avoided public criticism of it, and top officials have suggested the Soviets may be prepared for more serious negotiations than in the past.

The White House officials said Reagan's letter proposed to Gorbachev that Shultz and Shevardnadze meet soon, perhaps in Europe, to work out an agenda for the next summit. Shevardnadze had been scheduled to meet Shultz in Washington in May, but the Soviets canceled the meeting following the U.S. bombing of Libya April 15.

A series of Shultz-Shevardnadze meetings was held in Washington and Moscow in the months leading up to the first Reagan-Gorbachev summit meeting last Nov. 19-21 in Geneva.

A senior White House official said that before Reagan's letter was sent, the presumption had been that Shultz and Shevardnadze would not meet until the United Nations General Assembly convened in September.

Officials have assumed that the summit would follow in November or December. Reagan predicted in his news conference last week that there would be another summit with Gorbachev but did not say when. Gorbachev agreed to come to the United States this year when he met with Reagan last November.

Reagan said several times last week he is seeking a "better deal" and a "replacement" for the unratified SALT II pact, which the United States had previously vowed not to undercut.

Reagan said the United States would not exceed the limits of SALT II until the 131st B52 bomber is armed with air-launched cruise missiles later this year and that the decision whether to exceed those limits will take into account Soviet arms-control policies, including progress at the Geneva talks.

The president's remarks stirred confusion because they appeared to leave open the possibility the United States would not exceed the SALT II limits later on, but also defended the decision to abandon those limits. The White House said later that while SALT II limits no longer exist, restraint by the United States "is not dead."

The president, in his nationally televised news conference Wednesday night, also appeared to go out of his way to describe Gorbachev as the first Soviet leader to want arms reductions.

It could not be learned whether Reagan addressed the SALT II issue or the new Soviet proposal on strategic weapons in his letter to the Soviet leader. The London Observer, which disclosed the letter in its Sunday editions, said the head of Occidental Petroleum Corp., Armand Hammer, engaged last week in a round of personal diplomacy aimed at getting the summit schedule back on track.

Hammer met in Washington with Reagan and then called on British Prime Minister Margaret Thatcher in London and also on the Soviet ambassador to Britain, Leonid Zamyatin. He assured them Reagan genuinely wants a summit and to reach agreements with the Kremlin despite his recent hard-line statements, the newspaper said.