Chairman Mao would have been astounded.

And a group of Peking construction workers looked bewildered, as visiting U.S. automobile executives turned over 20 gleaming, midnight blue Cadillac limousines to Chinese purchasers today in a gold-key delivery ceremony.

None of the observers at the outdoor ceremony held just off a main Peking avenue was quite sure how the 20-foot-long Cadillacs would negotiate some of Peking's narrow alleyways or how they would stand up against their main competitors for space -- the more than 5 million bicycles, one for every two Peking residents.

According to John O. Grettenberger, Cadillac's general manager and General Motors vice president, this was Cadillac's first sale and delivery of a luxury limousine fleet to China.

The cars were purchased by the China International Trust and Investment Corp., the organization through which China hopes to attract foreign investment, and delivered in a ceremony outside the corporation's new 30-story headquarters, the tallest building in Peking.

Five of the new Cadillacs were new generation, front-wheel-drive models, with the most advanced computer components. They sell in the United States for just under $33,000, Cadillac officials said. The other 15 rear-wheel-drive Cadillacs, converted by O'Gara Coachworks at their Simi Valley, Calif., plant, go for a slightly higher price because they include accessories such as 10-inch color televisions, four-speaker AM-FM cassette stereos, lead crystal decanters, intercom systems, and illuminated ice service compartments.

The corporation's chairman, Rong Yiren, said the Cadillacs would be used by distinguished visitors to China and possibly by some of the nation's leaders. He declined to say exactly how much the corporation paid for the cars. There was speculation that General Motors had given the Chinese a good price as a sweetner for more sales of other types of GM cars.

Luxury limos are not unknwown to China. The late Communist Party chairman, Mao Tse-tung, was said to have been driven around in a stretch Mercedes from time to time, and Mercedes-Benz cars, including some taxis, are now seen frequently on Peking's roads.

Grettenberger was asked whether he expected any negative reaction from Chinese to "such an obvious display of affluence" in as poor a country as China.

He replied that he hoped reaction would be "positive . . . rather than negative," adding that he was sure the cars would be put to use "in the best interests of the People's Republic of China."