Trade officials of Peking and Washington have seized on a novel solution to sluggish sales and mutual inscrutability: a trade show featuring glossy brochures, how-to seminars for mystified U.S. business leaders and enough social events to schmooze Sino-American differences away.

The Economic and Trade Exhibition of Peking is scheduled to open tomorrow at the Washington Convention Center amid a flurry of receptions and prognostications that, indeed, the District's sister city relationship with the Chinese capital will bring tangible rewards.

The trade show, the largest sponsored by Peking outside of China, includes a variety of China's export goods, a collection of antiquities and a two-day seminar covering such topics as "Key Principles of Doing Business in China."

Chinese officials promise to explain their trade needs, customs and labyrinthine bureaucracies, while Americans in turn are expected to eyeball Chinese wares and maybe cut some deals.

"During the trade show we will sign some contracts," predicted Zhang Ming, deputy director of the Peking Municipal Foreign Economic Relations and Trade Commission.

At the very least, the principals on both sides will be well fed and watered. Separate receptions and luncheons are planned by Citicorp, Pepsi-Cola International, Coca-Cola and the National Bank of Washington.

"That's the way things are done," explained Courtland Cox, a District economic development official who helped set up the trade show, which runs through Oct. 4. "When you go to Peking they are very gracious and hospitable and so forth. You have got to show off your city. It is really about contact and having that one-to-one meeting and follow-up. It is best done in a social setting."

The trade show and its social trimmings arise out of the conviction on both sides that trade between the nations has not met expectations. Last year two-way trade totaled $6.1 billion, according to the National Council for U.S.-China Trade, but a more fluent trade relationship has been hampered by misunderstanding. China, the world's most populous nation, ranks only 19th in trade with the United States.

"I think the most important thing is that China is very different from America," Zhang said. " . . . I contacted many American businessmen in a few years. I find they didn't understand China very well. They don't understand the procedure of investments in China."

After Peking Mayor Chen Xitong visited the District in 1983, Mayor Marion Barry traveled to Peking in May 1984 and signed the sister city agreement that paved the way for the trade show. The District will hold a reciprocal show in Peking next spring.

Barry, while cautioning that these are "just the beginning steps between the municipalities," said this week that the relationship holds out the promise of job and entrepreneurial opportunities for businesses in the District and elsewhere. For Distict officials, close ties to Peking are seen as boosting the District's bid to become a business and financial center.

Curtis McClinton, the city's deputy mayor for economic development, said export opportunities are especially ripe for District firms in the printing, food processing, telecommunications and information industries.

The Chinese, for their part, are here to sell textiles, clothing, crafts, electronics, shoes, chemicals, canned goods and other products. Their biggest import needs from Americans, said Zhang, are high technology and industrial equipment.

"We prefer to have cooperation, joint ventures," he said. "There are about 14,000 factories in Peking but most of them were established in the 1950s and 1960s. We want to rebuild these factories."

Good trade intentions such as these, however, have foundered on the shoals of misunderstanding ever since President Nixon opened the door to U.S.-Chinese relations in 1972.

Whether feigning delight in Chinese delicacies such as sea snails or mastering the triple layer of government commissions that regulate foreign trades, Americans have sometimes found commerce in the Middle Kingdom mysterious.

The Chinese enjoy a reputation as tough negotiatiors who place great emphasis on correct social conduct, said John Callebaut, director of development and government relations for the National Council for U.S.-China Trade.

"When you first get there, they really don't want to sit down and talk business," he said. "Chinese want to get to know you. They don't care if you're big or small, they want to get to know you. They won't talk turkey until they get to know you. They talk about, 'How do you like the weather? Have you seen the Great Wall?' It's frustrating."

In addition, said Callebaut, the Chinese lack an efficient infrastructure to help accommodate trade.

"The phones don't work too well," he said. "Traveling around the country is different. The Chinese have to understand that they are competing with other Asian countries for business."

Bob Donovan, vice president and general manager of Babcock & Wilcox International, said it is the Chinese legal and governmental system that poses the greatest challenge to Western businessmen. His company has spent years putting together a joint venture with Peking to build a boilerworks.

"I think with China the biggest difficulty is identifying exactly what their legal structure is . . . . Their institutions are evolving so fast that it is very difficult to get good legal advice, financial advice," he said.

District and Peking officials are touting the two-day seminar, for which about 100 U.S. companies are expected to pay $350 each to attend, as a forum for explaining these complexities.

"This is the first time for the seminar," said Zhang, one of the speakers. "So I am not sure we get success."

Zhang said he will attempt to explain to the participants how government regulation of foreign trade works in his country.

"When we cooperate to build a factory, there are three commissions they American companies must go through," he said. "You know in China, there is the planning commission in charge of long-term planning for the city, utilization of the land.

"If the commission gives you permission, you can go to the second step, a feasibility study that is performed by both sides. The economic commission is in charge to check the feasibility study. American people don't know the difference between the planning commission and the economic commission. The third step is the foreign relations and trade commission."

There are many perplexing procedures that lay in wait for Chinese who would do business here, too. But these will have to await explanation at the District's trade show next spring.