The Reagan administration abruptly relieved two acting officials of the Arms Control and Disarmament Agency yesterday on the eve of two important government meetings dealing with arms control policy, according to sources within the State Department and on Capitol Hill.

Sources said Michael Pillsbury, acting deputy director of ACDA, and David S. Sullivan, the acting counselor, were called to the office of the new acting director, James Hackett, yesterday afternoon.

Hackett reportedly told them that he was acting under instructions and that they should turn in their security clearances and identification badges and leave by the end of the day.

Pillsbury, when asked by a reporter, confirmed this, stating that "I was notified that the transition team was terminated without any further explantion." Pillsbury said he and Sullivan were complying with the request. e

Both officials had been working since January on the administration's transition team, both have some conservative senators' support and both hoped for permament posts in the arms control agency.

Transition teams at the Pentagon, State Department and Central Intelligence Agency were disbanded months ago, but the adminstration appears to have been great difficulty figuring out who it wants to run ACDA, and the agency has been the focal point of recent political battles.

Pillsbury, who had worked for the Republican steering committee in the Senate for two years before going to ACDA and for the Rand think tank for five years before that, had become a specialist on negotiation with Moscow of limitations on medium-range theater nuclear weapons in Europe

Pillsbury accompanied assistant secretary of state Lawrence Eagleburger to a recent European meeting with allies about how to approach these negotiations.

Sources said the Cabinet will meet today, perhaps with the president in attendance, to discuss the timing of possible future negotiations with Moscow on this subject, which is viewed as crucial by the NATO allies. Pillsbury is said to favor going ahead with the negotiations.

Sullivan, a former CIA emplolye, has specialized on possible Soviet violations of Strategic Arms Limitation Treaty agreements. He has a list of incidents which he is widely reported to believe are SALT violations; other officials do not share his view.

Sullivan has become the center of some controversy within the administration. He was forced to resign from the CIA in 1978 after acknowledging that he had supplied secret documents to a senator's aide, and he ran afoul of former CIA director Stansfield Turner in the transition.

Sources said an interagency working group led by Richard Burt, director of the State Department's burearu of politio-military affairs, is to confer tomorrow on the SALT compliance question, which is due to be discussed in Geneva in late May by a special consultative commission.

White House officials declined last night to discuss agendas and would not confirm such meetings. They also said they assumed that Pillsbury and Sullivan would stay on the payroll until they located elsewhere.

Eugene V. Rostow, nominated to become ACDA director, is expected to come here next week to take over from Hackett.

Last night, sources close to ACDA said the dismissals might be reconsidered. What triggered the dismissals with such speed was White House annoyance at discoverying that Pillsbury was about to board a plane to Israel without White House knowledge.

Pillsbury apparently had arranged the trip to discuss with the Israeli defense minister the administration's decision to sell five AWACS radar surveillance planes to Saudi Arabia.

Sources said laws governing ACDA require a statement from the director on the impact of various overseas arms sales, and this apparently is what Pillsbury wanted to discuss.