As Chinese throughout the country set off fire-crackers in celebration, Peking announced tonight that the 11th National Communist Party Congress had met and officially declared an end to a decade of political turmoil.

The New China News Agency said Party Chairman Hua Kuo-eng told 1,510 Congress delegates that last fall's purge of party dogmatists "marks the triumphant conclusion of our first Great Proletarian Cultural Revolution, which lasted 11 years."

"Now," the agency said in summerizing Hua's address" . . . we are able to achieve stability and unity and attain great order across the land in compliance with Chairman Mao's instructions."

The announcement came as Secretary State Cyrus Vance flew from Washington to China to explore prospects for full diplomatic relations with the Chinese mainland. He will arrive in Peking Monday.

Hundreds of thousands of Peking residents poured out into the streets to fill the muggy air noise after the annoucement.

"They're beating the drums right outside my window," said a Western diplomat reached by telephone. Merrymaking in other Chinese cities was also reported at the conclusion of the first party Congress since the death of Mao Tse-tung September 9 and the first in four years.

Hua's speech along with addresses at the Congress by the other two members of China's Big Three, party Vice Chairman Yeh Chein-ying and Teng Hsiao-Ping, offered few surprises, at least in the summaries provided by the Chinese news agency.

The speeches emphasized unity and production and marked a turning from the disruptive political struggles between pragmatists and dogmatists that began with the Cultural Revolution in 1966.

Hua's administration has constantly streesed this theme since he purged four heroes of the Cultural Revolution, including Mao's widow Chiang Ching, in October, although this was the first time Hua actually declared the Cultural Revolution at an end.

The agency said the Congress opened Aug. 12 and ended Thursday. Following Hua's speech on the general political situation. Yeh reported on revision in the party constitution, much of it apparently designed to strengthen party discipline.

The Congress elected a new Central Committee of 201 full members and 132 alternate members, the agency said. The list of those elected indicated that no current member of the ruling party Politburo had been purged in the wake of last fall's major shake-up, but it also confirmed that dozens of lesser members of the previous Central Committee had been removed, undoubtedly because of their relationship to Chiang Ching and what the Chinese call her "Gang of Four." Among those gone from the new list was a Vice Premier Sun Chien.

Among the current Politburo members, one who received unusual prominence in the announcement was Wang Tung-hsing, a former body guard of Mao Wang, whose influence with the crack army until providing security for China's top leaders may have had great importance in last fall's purges, was listed as a vice chairman and secretary general of the Congress presidium. Television ooverage of the Congress seen here tonight seemed to give Wang fifth place in the ranks of party leaders, an improvement of a notch or two for him, but it was impossible to determine if there might be any other shifts because all the other prominent officials were listed in what passes in the Chinese language for alphabetical order.

Analysts await a report of the First Plenum of the Central Committee, which may come very soon, to see which of they younger Chinese leaders have been promoted to a Politburo that has been decimated by death and purges.

The news agency reported that the Chinese Communist Party now had 35 million members, an increase of about 5 million from the last reported figure. This growth seemed at odds with Hua's often cited contentions to weed out party members who swore allgiance to the Gang of Four or who were brought in without proper qualifications. Yeh's report mentioned that a one-year probationary period would be required of new party members "so as to insure their political quality."

As Peking prepares for Vance's visit. Hua offered the Americans the usual backhanded compliment that "the Soviet Union and the United States are the source of a new world war, and Soviet Socialist Imperialism in particular presents the greater danger."

The speakers at the Congress spread great concern over the quality of work by the Communist Party members who compose China's elite. They had high praise for veteran party officials who has done their best to serve the people. Teng, who since his recent rehabilitation has been held out as an example of that type, called in his speech for "seeing truth from facts, conducting criticism and self-criticism, being modest and prudent and free from arrogance and impetuosity."