When George Shultz rose to address American businessmen at a breakfast meeting here 19 months ago, his audience was prepared for the kind of tub-thumping, pro-Taiwan harangue typically given by visiting captains of industry.

Shultz had just been considered for high posts by the new president, Ronald Reagan, whose ardor for Taiwan was well-known. Shultz had come here as head of the Bechtel Group Inc., which does millions of dollars of consulting work annually for the Taiwan Power Co.

Yet Shultz's remarks did little to spice up the bacon and eggs served that morning at Taipei's sprawling American club, according to one witness.

"If you measured him against other business executives who visit Taiwan, he was tepid in his expressions of support," the witness said. Shultz spoke of the importance of sound U.S.-Taiwanese relations, but "he certainly did not go overboard," the witness said.

Now that Shultz is secretary of state, Chinese analysts on both sides of the Taiwan Strait are sizing him up not as a business executive but as chief architect of U.S. foreign policy at a crucial time in Sino-American relations.

While the Communist rulers in Peking have been reticent about Shultz, they undoubtedly feel the loss of his predecessor, Alexander M. Haig Jr., a forceful advocate of the mainland who left office recommending ways of accommodating China's concerns about U.S. arms sales to Taiwan.

Taipei, which feels it has been jilted and ignored by successive secretaries of state dating back to the Nixon years, is quietly optimistic that it has a friend in Shultz, who has visited the Nationalist Chinese stronghold five times since 1975 and is familiar with Taiwanese leaders.

Even if Shultz's support was lukewarm at the American Club breakfast, officials and political pundits here believe that his world view, background and temperament are more favorable to the island than Haig's.

While Peking was attracted by Haig's preoccupation with the Soviet menace, Taipei found him a bit too single-minded. He seemed willing to sacrifice the vital interests of an old ally, Taiwan, to appease the mainland, thus enhancing U.S. leverage against Moscow on the global chessboard.

If Haig was the retired soldier who conducted foreign policy like a battlefield commander out to win at any cost, Shultz is seen as the prudent corporate executive wary of putting all his capital in one place. Although he is expected to cultivate good relations with China, Taipei believes this will not be done to Taiwan's detriment.

"We're not looking for a pro-Taiwan policy, just a balanced one," explained Taiwan government spokesman James Soong in a recent interview. "Shultz seems to realize the importance of the continuing American ties to Taiwan.

"When Haig undertook a promainland policy because of Russia, our interests were totally ignored, We hope the administration will begin to focus on the future of Taiwan's 18 million people and stop using us as a pawn in global politics."

Shultz, known for his mediating skills, is viewed as a practical man who will support Reagan's foreign-policy philosophy, including his liking for Taiwan.

"People see Shultz as a professional who will do a good job of translating the president's policies without trying to craft his own," said Rob Parker, an American lawyer with close ties to the Taiwanese leadership. "There was a sense that Haig was on a different wavelength than Reagan."

Although no one is so presumptuous as to call Shultz a friend of Taiwan, officials seem to believe he has an understanding of their concerns simply because he has done business here for years.

Bechtel, the worldwide engineering and construction conglomerate that Shultz had headed since 1975, holds major consulting contracts for two of Taiwan's nuclear power plants. An affiliated engineering company called Pacific Engineers and Constructors Ltd.--60 percent owned by Bechtel--earns between $2 million and $3 million yearly performing support services for the two plants, according to a company executive in Taipei.

The Bechtel affiliate, which employs more than 500 local engineers and occupies six floors of two modernistic office buildings in downtown Taipei, hopes to export its high-technology engineering services to neighboring countries in Asia, the executive said.

Aware of the congressional scrutiny of top Reagan administration officials with past Bechtel connections, Taiwanese officials have sought to downplay Shultz's former business dealings in Taipei.

Still, they say Shultz's experience in Taiwan will enhance his understanding of the island's complicated relationship with Peking.

"The people who have never been to Taiwan don't realize the kind of life we have here," said Wang Chi-wu, vice chairman of Taiwan's National Science Council. "Anyone who comes knows the desire of our people to continue this way of life. I can never remember Haig coming."

"Haig understood Europe very well and Asia hardly at all," said lawyer Parker. "Shultz would appear to have a better understanding of this part of the world partly because he's been here and partly because he hasn't focused on one part of the world to the exclusion of others."

Peking, which is prone to conspiracy theories in its foreign-policy analyses, has said nothing publicly about Shultz's one-time business affairs in Taiwan. The official Chinese press has warned him of damage to Sino-American relations if Washington continues selling arms to Taiwan, but it otherwise has reserved judgment on the new secretary of state.

While extending a grace period to Shultz, China has intensified its criticism of the Reagan administration's policy of arms sales to Taiwan, apparently worried that Haig's exit will create a vacuum that could be exploited by pro-Taiwan politicians.

Shortly after Shultz's appointment, the official New China News Agency said that American conservatives had "seized on the change" in secretaries "and raised a hubbub to exert pressure on the government in a bid to shatter the ongoing negotiations on the arms sales issue . . . thus bringing U.S.-China ties into retrogression."