SO THE TWAIN are getting to meet after all - or are they? On this occasion it's the East coming West, bearing gifts of cultural finery and extending an olive branch of goodwill. The Performing Arts Company of the People's Republic of China, 150 strong, is said to be the largest group of artists ever assembled for appearance outside China, and the unit's five-night engagement at Wolf Trap this week is sure to be a source of fascination and enjoyment. But there's also a good chance that the visit will leave most uninitiated Westerners - like myself - as perplexed as ever about the mysteries of the Orient. And to all the ancient enigmas will be added the mind-bearing paradoxes of contemporary Chinese society.

The Chinese managers and directors who have shaped the production - there are two complete programs, each embracing about a dozen segments - have endeavored to bring us as broad a panorama of Chinese performance art as possible within their given framework. The personnel of the company include singers, actors, dancers, acrobats and musicians, and a good many of these artists are adept in more than one realm. The centerpiece of both programs consists of excerpts from the repertoire of the Peking opera, that remarkable Chinese theatrical genre that is not "opera" at all in the Western sense, but rather a Gesamtkunstwerk involving interwoven skills of dance, gesture, mime, recitation, martial arts, acrobatics, music, visual dressing and stagecraft.

Other elements of the program include a scene from "Red Detachment of Women," one of the so-called "model revlutionary ballets"; folk dances intended to display the arts of such national subcultures as those of Tibet, Mongolia and Korea; and musical selections involving ancient Chinese instruments, along with traditional and contemporary songs.

I was able to chat with some members of the enseumble in New York, with the help of interpreters, and as we sat around quite informally in a hotel lobby, the atmosphere was extremely genial - the conversation punctuated with much laughter on both sides. The several company members, all men, were variously dressed in suits or slacks of relatively plain, but not uniform, color and design. All of them smoked Chinese cigarettes continuously. They offered me one - it was filtered and mentholated, I thought, with a mild, sweetish taste.

Unlike the Cuban Ballet people, who seemed very guarded in their recent visit on the subject of politics, the Chinese appeared to be very open and frank. They discussed freely the drastic changes in policy since the ousting of the repressive "Gang of Four" in 1976, and the subsequent efforts to restore traditional Chinese and Western modes of performance, along with the continued cultivation of "revolutionary" styles and content.

The Peking opera itself fell under a cloud during the "black decade" (the reign of the Gang of Four, roughly 1966 to 1976), and its resuscitation was made possible only through two circumstances, they told me. First, the older members of the troupe had long been involved with the Peking opera traditions, and were able to remember and transmit them to younger artists. Secondly, the techniques of the Peking opera, for example the martial arts and acrobatics, had had enormous influence on other Chinese forms, including the "revolutionary" repertory evolved during the suppression of classics, so that many of the ingredients were ready at hand when the "relaxation" arrived after the death of Mao Tse-tung.

But if the door has been reopened to venerable Chinese traditions and even to such formerly proscribed, "decadent" Western manifestations as classical ballet, the main thrust of contemporary Chinese performance seems to be the assimilation of all these forms towards the expression of Chinese themes and ideals.

Among my interlocutors was Li Cheng-hsiang, the choreographer of "Red Detachment of Women," and one of its performers as well. He had first studied ballet in 1950, he said, from both Chinese and European teachers, and was dancing in ballets like "Swan Lake" by 1958. "Swan Lake," he told me, and other Western ballet classics, are again being danced by Chinese troupes. But his own choreography is concerned with fulfilling Chairman Mao's dictum about letting the past serve the present - he uses traditional ballet techniques in behalf of contemporary Chinese subject matter. His newest ballet, for instance, "Fragrant Wood Song," deals with the ceremonial delivery of a rare species of wood for use in the erection of a memorial to Chairman Mao.

Li and others of the troupe had been taken in New York to see performances and lecture-demonstrations not only by the New York City Ballet and American Ballet Theatre, but also by such American modern dance apostles as Martha Graham and Erick Hawkins, who in their own past had been much under the sway of Eastern esthetic models. But though Li and the others found these encounters interesting and rewarding, they also remarked that they would probably strike a modern Chinese audience as "too absract."

By a similar token, the tour programs of the Performing Arts Company were designed specifically to appeal to a broad, unspecialized American public, with a consequent emphasis on the athletic, the showy and the picturesque, and an avoidance of rarefield Chinese vocal techniques and declamation (dependent on an under-standing of the language).

The one program I caught at the Metropolitan Opera tempted to confirm all this. Except for the Peking Opera excerpts - which were extraordinarily delicate and subtle in movement quality, and altogether entrancing - the bulk of the program seemed artistically slight, and thoroughly gussied up for Western consumption. The "folk" dance looked authentic in costuming only - the choreography was tricked up with various Russian-looking bravura gambits, and the music sounded like sugary dilutions of rustic materials. Somewhere along the line, the Chinese have learned the Western art of commercial packaging, and the result is a production that on the whole suggests a Chinese version of a Radio City extravaganza. When a traditional Chinese orchestra, as an encore, gave out with "Turkey in the Straw," the impression was complete.

The whole experience left an odd sense of turnabout. In contrast to the Orient, the Western strong suits have always been technology, pragmatic "know-how," and in the arts especially, realism. The East, on the other hand, has long been looked upon as a bastion of spiritually, refinement and exquisite stylization. In recent decades, however, Western artists have been avidly courting such "Eastern" values of meditative serenity and ritual detachment. Now, we have the prospect of the Chinese, bent on reaching the "masses" at home and abroad, striving for realism, literalism and kitschy sentiment.

Once long ago in Tokyo, I had been invited by a Japanese friend to dine with his family at home, and was looking forward to my first taste of authentic Japanese cuisine. To my regretful astonishment, my hosts brought forth a dish of Virginia ham, acquired at great pains to please a Western guest.

The parallel is far from exact, but the feelings evoked are akin. In the current Chinese esthetic export, and in the emissaries' eagerness to win over American taste, what is most original, precious and profound about Chinese traditional arts seems to have been largely subordinated to the impulse of cultural outreach. And, one suspects, both Americans and Chinese may be the losers.