Foreign ministers from the 35 signatory states of the Helsinki agreement on security and cooperation in Europe gathered here today in a generally disillusioned mood to mark the 10th anniversary of the accords, whose human rights provisions are widely viewed in the West as having been totally flouted so far by the East.

The East-West gathering has taken on added interest because it will mark the international debut of the new Soviet Foreign Minister Eduard Shevardnadze, who is to hold a three-hour private meeting Wednesday with Secretary of State George P. Shultz, the first meeting between the two.

U.S. officials, aware of the heavy pall of cynicism hanging over the accords and the 10th anniversary gathering here, seem to have gone out of their way in background briefings in Washington this past week to justify the continuation of the whole Helsinki process.

While acknowledging their disappointment with the general deterioration in the human rights situation over the past decade in the Eastern Bloc, particularly in the Soviet Union, they have been stressing the value of the accords as at least providing a "measuring stick" and legal basis for taking violators to task.

"The fact that the Soviet Union agreed to the Final Act, the fact that it took on these commitments and the fact that it is not observing those commitments provides us a means of legitimately raising these issues," Richard R. Burt, the outgoing assistant secretary of state for European affairs, told a skeptical British reporter on the U.S. Information Agency's Worldnet program last week.

The Helsinki accords are formally known as "The Final Act of the Conference on Security and Cooperation in Europe." They were signed Aug. 1, 1975, by the United States, Canada and all European countries except Albania.

The 40,000-word document, produced in the heyday of East-West detente, provided for the expansion of cooperation between the two blocs in trade, cultural, military and other fields such as tourism. For the West, perhaps the most important expected outcome was to be a freer flow of information, ideas and people between East and West, together with improved human rights in Eastern Europe.

For the Soviet Union, however, the main importance of the accords was the West's formal recognition of the territorial and political status quo in Eastern Europe resulting from World War II.

After four years of initial improvement and progress in many Eastern European countries in the human rights field, the situation started to deteriorate with the Soviet invasion of Afghanistan in 1979 and has grown steadily worse since.

One indicator often used to gauge the ups and downs in the Soviet record on human rights is the rate at which Moscow allows Soviet Jews to emigrate. From a high point of 51,000 in 1979, the flow has dwindled to about 900 last year. In May and June, the figures were the lowest since the death of Josef Stalin, according to U.S. officials.

The two sides have moved so far apart on human rights that when the third round of Helsinki review conferences was held in Ottawa last month to discuss those provisions of the accords, they could not agree on a final statement or even a common definition of what human rights means.

This widening gap in interpretations of the Helsinki accords has led to mounting criticism of their value in the West, particularly from monitoring groups in the United States. Their main focus has always been on the expectation of a freer flow of information and people.

Reagan administration spokesmen have sought to cast the importance of the gathering here of the signatory nations 10 years later partly in terms of the Helsinki accords' usefulness in publicizing the extent of violation of human rights by the Soviet Union and its allies and partly its potential for laying the groundwork for a new beginning to troubled Soviet-U.S. relations.

The Soviet human rights record, "in facts and deeds," as Burt put it, is expected to be one of the main topics of Shultz's address on Tuesday, the same day that Shevardnadze is scheduled to speak.

The other main significance of the gathering here, at least in the U.S. view, is that it will provide the occasion for Shultz to get acquainted with the new Soviet foreign minister.

U.S. officials hope to use the meeting not only to begin preparations for the summit conference in November between President Reagan and the Soviet leader Mikhail Gorbachev but also "to chart a course," as one put it in Washington last week, for improving relations between the two superpowers.

A senior administration official said Shultz intended to point out the need for progress in the stalemated Geneva arms control negotiations, assess problems in East-West conflict points such as Afghanistan, discuss bilateral issues and express concern about the violation of human rights in the Soviet Union.