West German Chancellor Helmut Schmidt strongly appealed to Leonid Brezhnev tonight to pull all Soviet troops out of Afghanistan to end "this dangerous crisis." He also asked the Kremlin to begin talks without preconditions on limiting nuclear weapons in Europe.

Schmidt, arriving here with Foreign Minister Hans-Dietrich Genscher for a two-day summit with the Soviet president and party leader, issued his appeals in a formal speech prepared for a Kremlin banquet.

He said the Afghan crisis "throws a wide shadow over East-West relations in Europe" and has brought "deep worry and anxiety" to nonaligned Third World countries, "especially Islamic nations."

But in earlier talks at the Kremlin, Brezhnev apparently showed little inclination to move from the Soviet position on Afghanistan. The official news agency Tass said Brezhnev told his West German visitors, "the notion about the events in Afghanistan existing in certain circles in the West proceed not from facts but from prejudiced attitudes to these events."

Brezhnev, 73, told Schmidt that a political settlement could be reached on the basis of the May 14 proposals of the Marxist government in Kabul. These call for recognition of the government of Babrak Karmal by Iran and Pakistan. "The question of withdrawal of Soviet troops," Tass quoted Brezhnev as saying, must be "involved in the context of the above mentioned political settlement."

The summit, the first in Moscow between Brezhnev and a Western leader since the Dec. 27 Soviet invasion, began today against a background of continued Western disagreement over a unified response to the Afghan situation. Accompanying this has been American nervousness over Schmidt's intentions toward NATO's decision to base medium-range nuclear missiles in Western Europe to counter a continued Soviet buildup.

But Schmidt, in his toast at the Kremlin, bluntly declared that the Soviets had gained military advantage over the West by deploying a new generation of medium-range missiles in central Europe, forcing NATO to counter. NATO agreed last December on an American plan to situate 572 advanced Pershing and cruise missiles in Western Europe, beginning at the end of 1983 when the weapons are ready.

Schmidt and President Carter have had uneasy relations to recent months over the chancellor's suggestion for a freeze on the missiles' deployment pending talks with the Soviets. In his toast, Schmidt noted that the NATO decision included an offer to Moscow to negotiate limits on the new arms.

"We have read a Warsaw Pact declaration of May 15," he said. "It speaks of a readiness for negotiations on all weapons. Make that readiness concrete by agreeing to prenegotiations on medium-range missiles without setting conditions," he said.

In his own formal toast, Brezhnev was noncommittal on this question, noting only, "Tommorrow, we shall talk about them, too. I would like to express the hope that our dialogue would be a fruitful one."

Washington expects the Kremlin to press Schmidt hard on the so-called theater nuclear forces question in its attempts to stall the NATO decision. Foreign envoys here are paying close attention to this aspect of the talks. One of them said after hearing the gist of Schmidt's proposal that he was reassured since the chancellor had not so far mentioned the notion of a "freeze" before entering talks with the Soviets.

On Afghanistan, Schmidt said the West and most of the world community supported calls early in the year by the United Nations and the Islamic Conference for the Soviets to withdraw. "The common goal of these decisions and initiatives is the reestablishment of an independent, nonaligned Afghanistan which corresponds to the wishes of the Afghan people and the legitimate interests of Afghanistan's neighbors," he declared.

I am sure that you . . . would contribute significantly to defusing the dangerous crisis if you could state that the announced withdrawal of some Soviet troops is the start of a continuous process that will go on until there is a complete withdrawal," the chancellor said.

The Soviets announced June 22 that they were pulling a division and 108 tanks out of Afghanistan. Western military sources estimate this is about 8,000 to 10,000 troops. Moscow has never disclosed how many troops it has in the country to secure Babrak's government, but Western analysts estimate about 85,000.

There are reliable reports from Kabul that the Soviets are altering the composition of their forces, reducing the armored elements and adding helicopters and other forces more suited to the kind of guerrilla warfare that has developed in the rugged, mountainous country between the Soviets and Moslem tribesmen, who have declared a jihad, or holy war, against the invaders.

Tass heavily censored Schmidt's critical remarks on Afghanistan and theater nuclear forces in its dispatches tonight, presaging how the Soviet press will handle his visit. The news agency, in a rare rebuke of a visiting government leader, later criticized Schmidt, saying he "failed to say a stop should be put on all aggression against Afghanistan, which, as is known, led to the request of the Afghanistan government for military assistance from the Soviet Union." Moscow has never accepted the Western charge that it invaded Afghanistan.

The Soviets and West Germans have been engaged in a quiet tussle for weeks over the diplomatic protocols surrounding this meeting, with Moscow eager to make far more of it than Bonn. The West Germans, consider it "a working visit," Schmidt's first since meeting here with Brezhnev in 1974, while the Soviets are trying to lay on the full panoply associated with a state visit.

Thus, Brezhnev himself met the chancellor at the airport today when he might normally have expected to be greeted by Premier Alexei Kosygin. The Kremlin wants to show the world, on the eve of the Olympics, that Afghanistan has not interrupted normal relations with the West.

The two sides met late this afternoon in the Kremlin's ornate Catherine Hall for the first formal session, which Tass said was "a frank and profound exchange of views," meaning there were fundamental disagreements. Late tonight, a West German government spokesman, Klaus Boeliing, said the session was "open, factual, and very serious," meaning the same thing.

He said Schmidt proposed a specific timetable for the total withdrawal of Soviet forces from Afghanistan, but Boelling refused to give details. He also said the chancellor, who is up for reelection in the fall and open to attacks from the left for damaging detente and from the right for keeping up relations with Moscow, had defended the United States against Soviet allegations that Washington was intent upon worsening relations between the superpowers.

Schmidt told Brezhnev that "whoever is concerned for world peace must renounce attempts to force his own politics, social and economic concepts on the Third World." He added his hope that the Kremlin would join the United States in announcing it will abide by the terms of the SALT-II arms limitation agreement even though the treaty has not been ratified by the U.S. senate.