Taiwan has begun a campaign to expand its trade with the United States and other nations in order to counter the effects of the U.S. diplomatic and military pullout from the islandd, businessmen and officials said here today.

At the same time, American businessmen said they would continue to enlarge their investments in Taiwan next year despite the island's diplomatic isolation from Washington and most of the rest of the world. Some business suggested that President Carter's announced commitment to protect "The well-being of the people of Taiwan" after the pullout could delay U.S. trade restrictions that might other wise have been imposed on Taiwan imports.

"We're projecting double digit percentage growth in loans in 1979 and 2 see no reason to change that projection," said Douglas W. Taylor, manager of Bank of america's Taipei office.

Economic experts said yesterday they saw little sign of any panic that would mar a year in which Taiwan's growth rate climbed from 8 percent to 12 percent. The economy could be hurt by a recession in the United States or growing foreign tariff barriers, but the announcement of the U.S. diplomatic pullout seemed to have little initial adverse impact other than an expected drop in the local stock market.

Resolution from a meeting of 400 Taiwanese business and industrila leaders released today called from "expending foreign trade and technical cooperation with foreign sources to win friends and markets in the world."

In a speech at a meeting of the Central Committee of the ruling Nationalist Party yesterday, Premier Y. . Sun emphasized the need to keep trade with the United States going despite the diplomatic pullout.

The United States is by far the largest customer for Taiwanese goods, buying about 40 percent of the island's total annual exports of the about $13 billion, The United States, however, provides only 23 percent of Taiwan's imports, and the government here has tried to narrow the trade gap by organizing special "buy American" missions to the United States.

Taiwan has in the last several years been actively encouraging foreign financial involvement here both to keep this mineral-poor island's economy alive and to win much-needed friends abroad as embassies here close up and move to Peking. The U.S. Ex-Imbank and private American banks have loaned an estimated $4.4 billion to island enterprises. Direct American equity capital here totals about $500 million.

American bankers interviewed yesterday said they expected that investment to grow.

"Our policy continues tou be aggressively seek out more business opportunities," said Tom Maher of Chase Manhattan Bank.

Ford Lio Ho, the local subsidiary of Ford Motor Co., announced it was investing $39.5 million from this year through 1980 to raise vehicle production from 65 to 170 automobiles a day.

General Instruments here said it was bringing in more equipment to expand its electronic components production.

Taiwanese officials have spoken this week of their determination to finish the $7 billion "ten great construction projects" on schedule next year and begin the planned "twelve big projects" aimed at transportation and energy independence.

When Japan moved its embassy from Taipei to Peking in 1972, the shock sent the black market exchange rate for one U.S. dollar from about 43 new Taiwan dollars to 54.

It was a sign that many residents here wanted U.S. currency in panicked preparation for a sudden move to the United States. In the first three days after President Carter's announcement this weekend, however, the black market exchange rate barely inched up from 38.4 to 39 new Taiwan dollars.

Several economic experts here said they thought local residents had already discounted the U.S. pullout in their planning. One Taiwanese businessman seeking a factory site in the southern part of the island said he had been told by a real estate agent in October to wait until April. By that time, the agent figured, Washington would have normalized relations with Peking and property prices in Taiwan would be lower."That 2ndicates there is no lack of interest in buying land, and so the price may not drop at all. I think its significant. You can't take a piece of land and leave the country," said one economist.

Robert Parker, president of the American Chamber of Commerce here, met today with Taiwan's minister of economic affairs to sort out strategy for countering any possible dip in the economy.

"There's no use pretending that normalization on the terms we got won't hurt. It will," Parker said. "But the economy is strong. It is a good government. The government has the support of the people and the people are equipped to defend themselves."

There have been suggestions that Peking might eventually attempt to organize an economic boycott of the island among the countries that have withdrawn their embassies, but officials here said they see no immediate sign of that.

On the contrary, Chinese leaders like Vice Chairman Teng Hsiao-ping have been promising to presefve living standards on Taiwan, at least when the island is "reunified" with the mainland.

(China has indicated it may be willing to establish trade and economic relations with Taiwan, according to dispatch from Peking's official New China News Agency today. The agency quoted Chinese Trade Minister Li Chiang as saying, "Taiwan is part of China. Why can't there be trading relations between Taiwan and the mainland?" The agency said Li made the remark yesterday at a news conference in Hong kong."

Anti-american demonstrations that erupted here shortly after Carter's announcement have subsided.

Both the U.S. Embassy and its consular section were open as usual today, after being closed yesterday. Taipei police began today to remove the metal and barbed wire barricades that had created a quarter-mile-wide no-man's-land around the embassy building since Sunday.