The Soviet Union said today that President Reagan's plan for deploying the MX missile would breach Soviet-American strategic arms limitation (SALT) treaties and bluntly accused him of using "seemingly peace-loving terms" to obscure his quest for strategic superiority.

The new Kremlin leadership gave its authoritative reply to Reagan's Nov. 23 speech on deploying the MX in an unsigned 3,000-word editorial in the Communist Party newspaper Pravda, which clearly had top-level approval.

The editorial reaffirmed the Soviet leaders' readiness to negotiate an "honest agreement" with the United States. But, it said, the Reagan administration, "judging by everything, does not wish to look for a reasonable and mutually acceptable accord."

If the MX deployment does get under way, the editorial said, the Soviet Union will find "an effective way to reply to Washington."

The statement purported to "ascertain and compare the essence of the positions" of the two superpowers "on problems whose solution will largely determine the destinies of mankind."

The tone of the editorial suggested that the new leadership under Yuri Andropov may adopt confrontational policies if the Reagan administration continues its arms buildup.

"Starting the implementation of the MX program, Washington should know that this runs counter to one of the central provisions of the SALT I and SALT II accords -- an obligation not to create additional silos for intercontinental missiles.

"Washington must also be aware that this step will not promote progress at the negotiations in Geneva," it said.

The statement described as "absurd" Reagan's so-called zero option at the Geneva talks on limiting medium-range nuclear arms in Europe. It said the plan envisages "the destruction" of Soviet medium-range weapons while "leaving intact" the similar weapons of Britain and France and U.S. forward-based "nuclear means."

It quoted Andropov as saying that American statements linking "readiness for normalization of relations with the demand that the Soviet Union pay for this by some preliminary concessions in various spheres sound, to say the least, not serious. We will not accept this."

The statement described as "positive in character" Reagan's proposal to improve the Moscow-Washington "hotline" and other confidence-building measures, but said it was more important to reduce the levels of arms on both sides than to improve communications.

"If for every 100 MX missiles we add 10 telephones linking Moscow and Washington, red ones or blue ones, does this make the missiles any less dangerous?" the statement asked.

Diplomatic observers here said Reagan's MX speech came at a particularly inopportune moment: when the new Kremlin leadership was getting organized, and following the visit here of Vice President Bush and Secretary of State George P. Shultz which raised hopes for an easing of tension in Soviet-American relations.

The English-language newspaper Moscow News said today that the meeting of Andropov with Bush and Shultz was intended as a "sign" to Washington that Moscow would like to arrest the steady deterioration in relations. It said recent American pronouncements indicated that the Reagan administration was turning its back on this opportunity.

Commenting on Reagan's statement that "it takes two to tango" and reported U.S. demands for Soviet concessions, the paper said: "Taking the president's analogy further, one might note that asking someone to dance is not generally done by a demand that he or she change their hairdo, let alone thinking. The partner is taken for what he or she is."

The statement in Pravda, which was also distributed by the government news agency Tass, was even more harsh. It accused Reagan of deliberately deceiving the American public by contending that the "road to peace was paved with new missiles, new nuclear charges, new planes and ships."

It said Reagan resorted to "rudest exaggerations and distortions" to depict Moscow as the initiator of the arms race. The editorial said Reagan showed "the naive television viewers colored diagrams and charts in which everything could be detected except the truth." It was an "irrefutable fact that the arms race has its roots in American soil," the statement said.

The statement asserted that Reagan "must be aware that the Soviet Union will not tolerate a lagging behind in aspects which are vital for its security." It said Moscow had found it "necessary to mobilize additional forces and resources for the improvement of its armed forces" to meet earlier American challenges and would do so again.

Pravda gave detailed figures on U.S. weapons systems developed in the postwar period. It said that Moscow had proposed that both sides renounce the development of new weapons systems and that it had advocated measures to prevent "militarization of outer space."

But, it said, "none of these and similar proposals has found a positive response in the United States." It said the Russians were forced to build their Typhoon nuclear submarine to counter the American Ohio sub.

"Why should one spend innumerable billions for the creation and production of increasingly destructive systems of weapons when an opportunity exists to maintain security at lower levels?" the statement asked.

The editorial answered by asserting that Reagan had "plainly explained that the purpose of the deployment of the MX missiles and other armaments is to achieve an incontrovertible military superiority over the Soviet Union and to create prerequisites for ensuring an American victory in any conflict, including a nuclear one.

"Counting on a victory in a nuclear war is adventurism. It is doomed to failure. The Soviet Union does not intend to chase the United States in the creation of each new system of weapons or to imitate the United States. This does not mean at all that the Soviet Union will not find an effective reply to Washington if the United States begins realizing its plans."