European members of the North Atlantic Treaty Organization joined the United States today in aiming some harsh rhetoric at Soviet behavior around the world.

At the conclusion of the NATO foreign ministers' meeting here, the 15 member countries issued a communique that sharply criticized Soviet activities and implicity linked improved East-West relations to a lessening of aggressive Soviet actions.

In what was perhaps the key phrase of the communique, the ministers said their governments "will maintain a dialogue with the Soviet Union and will work together for genuine detente and the development of East-West relations, whenever Soviet behavior makes this possible."

This stress on the principle of linkage reflected the attitudes that the Reagan administration has been trying to apply to U.S. foreign policy. Its adoption here by Washington's allies followed yesterday's announcement by Secretary of State Alexander M. Haig Jr. of the administration's willingness to pursue talks with Moscow aimed at possible future negotiations on limiting intermediate-range, nuclear missiles based in Europe. The Europeans have expressed a strong desire to get arms talks under way.

Today, Haig told the European foreign ministers the United States will initiate preliminary talks with the Soviets leading to discussions between Haig and Soviet Foreign Minister Andrei Gromyko at the United Nations in the fall with the eventual aim of beginning the arms-limitation talks by the end of the year.

The U.S. move was aimed at easing the concern of NATO members in Europe that are supposed to become the sites of new generation U.S.-made Pershing and Tomahawk missiles capable of striking into the Soviet Union. Deployment of these missiles is scheduled to begin in late 1983.

However, several West European governments -- notably West Germany, Italy, the Netherlands and Belgium -- had become alarmed that deepening pacifist sentiment within their countries could imperil the missile-deployment plan unless NATO demonstrated willingness to talk with the Soviets about arms limits. The offer conveyed by Haig to do that is known to have sparked great relief among the Europeans.

In addition, they also are known to have been encouraged by Haig's revealing, in a closed meeting here, that Reagan recently sent a letter to Soviet President Leonid I. Brezhnev stating U.S. willingness for a dialogue on a broad variety of issues. According to reliable sources here, the Europeans, as a gesture of reciprocity, agreed to the communique language that the United States wanted as a signal to the Soviets on several points where President Reagan and Haig have said the West must take a firmer stand.

As a result, the ideas being pushed by Washington run through today's communique almost from the opening paragraph, which states: "The strength and cohesion of the alliance . . . requires that all nations act with restraint and responsibility. Claims by the Soviet Union that it too subscribes to such policies are not borne out by Soviet deeds. The more constructive East-West relationship which the allies seek requires tangible signs that the Soviet Union is prepared to abandon the disturbing buildup of its military strength, to desist from resorting to force and intimidation and to cease creating or exploiting situations of crisis and instability in the Third World."

That point is made repeatedly in the communique's comments on various issues facing the alliance. In one departure from NATO's usual practice of concentrating its attention primarily on European defense concerns, the communique, as the result of U.S. pressure, devoted considerable attention to alleged Soviet intervention and aid to insurgent forces in the Third World.

The text said: "Genuine nonalignment is an important factor for stability in the world. The allies will continue to consult among themselves and to work together with others to encourage stability and reduce the risks of crisis in the Third World. . . .

"The maintenance of this independence, peace and international equilibrium is a vital interest of the West. Political settlements must be found to crisis or conflict situations."

The statement called on the Western democracies to offer development help to Third World countries and said: "All states must refrain from exploiting social problems or fomenting instability for political advantage." It added, "a number of allied countries possess, or are determined to acquire, the capability to deter aggression and to respond to requests by nations for help in resisting threats to their security or independence."

On the subject of gravest concern to Europe -- the continuing crisis surrounding Poland -- the communique repeated past Western warnings in especially strong terms: "Poland must be left free to resolve its own problems. Any outside intervention would have the gravest consequences for international relations as a whole and would fundamentally change the entire international situation."

At a press conference following the meeting, Haig repeatedly expressed his happiness at the "strong language" in the communique and said it demonstrated that the alliance is in accord with the Reagan administration's views about the need for unity and strength in confronting the Soviets.