China is a much older melting pot than America and they have many strains in their culture, so it was none too surprising to hear the baroque Italian strains of Arcangelo Corelli floating over the Chinese reception yesterday at the Washington Hilton.

A thousand people, friends and well-wishers of the People's Republic -- many of them working for years to promote the eventual recognition of the Peking government by Washington -- attended a reception given by the National Association of Chinese-Americans.

People either were curious to see how the party would go, or else felt they had waited long enough for that day on general principles, and so hundreds arrived early.

By 3 o'clock, the time the party was supposed to start, the International Ballroom was doing a brisk business in Tokay grapes, Roquefort cheese, and a punch said to depend on cranberry juice, ginger syrup and champagne.

Guests signcd a great crimson silk sheet in heavy black ink -- the ones who could manage Chinese characters signed with them, but others just printed Roman letters -- and strolled about among the scarlet candles, red and white flowers, pausing to take a puffy pastel-tinted potato chip from little bowls on tables at the edge of the room.

Television lights began to blaze as the People's hepublic walked in, headed by Ch'ai Tse-min, chairman of the liaison office.

He is former ambassador to Thailand, Egypt, Hungary and Guinea, and some expect him to be named People's Republic ambassador here. The No. 2 man, Han Hsu, who is also called ambassador, is the deputy chief of the liaison office, and they were accompanied by aides and interpreters.

"We think it is a day of great significance," said Ch'ai, before the crowd around him had thickened very much, "long awaited and expected,and now it is a reality."

Later he read a short speech in Chinese along similar lines, clapping his hands neatly (like the Russians) whenever the audience interrupted him with applause. He wore a high-collared jacket of black, with shining black buttons down the front.

His eyebrows are horizontal, straight and bushy, and he has a sturdy muscular frame. In talking with you (his interpreter at his side) he has a pleasant face, not foolishly smiling, but very agreeable and he has frank eyes.

After his speech, he toasted the audience with a Happy New Year and sat down quietly to his glass of red punch, registering neither interest nor lack of interest. One felt he had got used to drinking whatever was served at ceremonial functions.

Dr. Chen-Ning Yang greeted guests, heading a short receiving line. He is president of the National Association of Chinese-Americans, and is Albert Einstein professor of physics at the University of New York at Stony Brook. He won the Nobel Prize for physics in 1957.

He was educated in wartime China and came to America in 1945. Like many Chinese-Americans, he spoke of the brightness of possible family reunions. Many families have been separated 30 years.

Van Lung, a leader of the Chinese community here, who was host for the People's Republic delegation when it was first established, was busy introducing people -- he seemed to know everyone present.

Among Americans present, not all had Oriental faces. An old lady with a bent posture walked about with a stick to support her. A white-haired man of intellectual face sat on a chair in the middle of the traffic with a large glass of ice water and a look of having been interested in idealistic causes 50 years ago. A number of thick-haired WASP types were students.

Jacqueline Lenchek of Washington, one of 375 local members of the U.S.-China Peoples Friendship Association, handed out booklets about that group. But often friends stopped to talk, and her eyes registered distress at the number who entered without her asking them if they didn't want to join.

A Yamaha grand piano struck up with some Chinese songs in Chinese, sung by a soft chorus of young people, and later a woman played the er-hu, a one-stringed instrument that is fingered and bowed to produce a haunting melodic line.

Otto Preminger, the filmmaker, flew down from New York for the party. He stood looking down at the animated silks and happy faces, and told reporters:

"I was in China about three months ago, and I was there in 1949, and the progress that has been made is incredible.

"Believe me, I am not a Communist," and his blue eyes gazed straight at you, "but before this present government came to power I saw little children in the streets of Peking and Shanghai. Sitting in the gutter. Almost nude -- in rags. Eating mud with their fingers because they were so hungry.

"This last visit, everyone said now nobody is hungry. Of course Chiang Kai-shek could have made the same kind of progress if he had not been so greedy. It's not that they're Communists, but that they've divided the food so all can eat.

"It is silly, just silly, to recognize 17 million in Taiwan and ignore 900 million in China.

"There is no doubt in the future China will be one of the greatest powers, maybe the greatest in the world.

"I don't know what to think of (Sen. Barry) Goldwater who is senile, trying to sue President Carter for the treaty. With what chance of success, you well know."

Preminger made the same comments addressing the entire ballroom, except he did not call the senator senile, which might have seemed rude. He said the senator was "older than his years."

Someone asked the filmmaker if he by any chance wanted to shoot film in China and he said that as a matter of fact he did, but for years had been denied permission. He thought permission was coming now.

Once he nodded to Ch'ai and said:

"You will think I am hired to sing the praises of your government but I'm not, and this is impromptu. It's just that I have been so impressed. In China there is suddenly a new spirit of doing things, of creating things.

"I speak only for myself, not for Americans as a group, but I am so glad Carter, for once in two years, did the right thing. I voted for him and can say that. This is the first great achievement of Carter in his two years of office."

Everybody clapped enthusiastically.

Ch'ai's speech was one of optimism as he spoke of the contributions Taiwan could make to the reunification of China. This reunification, he said, was the "common aspiration" of all Chinese.

"All compatriots belong to one family," he said, but "at present there is a new 'Long March' for the modernization of China," The hope and aim, he said, is "a modern socialist power within this century."

Van Lung said:

"Time was reserved for a representative of our own American government, some official of the State Department or the White House. But as you can see, they are late. (Laughter, since the party was almost over.) Our government seems to be always late."

In fact, however, Vice President Walter Mondale, Secretary of State Cyrus Vance and other officials attended a reception at the Chinese embassy later, where things went swimmingly.

Still, as Ch'ai had said, to great applause, "From today on, a new pageis open."

In time the punch bowls ran dry and even the carved grapefruits, meant to be decoration, were eaten. Waste not, want not. Gaily decorated station wagons took some guests away, the roofs flying little American and Chinese flags, and the liaison officers, some in gray and some in black, got in a plain sober station wagon and drove off.

Many outside the hotel who were just strolling along the sidewalk, could be seen looking seriously at the Chinese flag -- red with one large gold star in the upper left field, with a semicircle of gold stars to its right.

"This," said the Nobel laureate, "is a great day."