Retired CIA analyst Larry Wu-Tai Chin gave classified information to Chinese intelligence officers not to hurt the United States but to help bolster a faction of the Communist government that wanted a reconciliation with this country, his lawyer told a crowded federal courtroom in Alexandria yesterday.

A federal prosecutor, however, said Chin's motivation was money and that "for over 30 years Chin lived a lie and a double life," passing secret documents detailing what the U.S. intelligence community knew about China's military, political and economic conditions.

These contrasting portraits of Chin, who is accused of spying for China since 1949 while working for the Central Intelligence Agency, emerged yesterday on the first day of his trial in U.S. District Court on charges of espionage, conspiracy and violations of income tax and financial reporting laws. If convicted, the 63-year-old naturalized American could be sentenced to life in prison.

Providing the first glimpse of Chin's defense to the charges, his attorney, Jacob A. Stein, disclosed that Chin will take the witness stand to describe how he gave only information "which would put the U.S. in the best light."

Stein told the jury of nine women and three men that, while Chin was working as an interpreter with the Foreign Broadcast Information Service, he observed a conflict going on in China between factions led by former premier Chou En-Lai and by former Communist party leader Mao Tse-Tung.

Chin "wanted Chou to prevail and he wanted to play a part in that," Stein said. For example, Stein said, at a critical juncture in President Richard Nixon's then-secret efforts to normalize relations with China, Chin informed his Chinese contacts of Washington's intentions. This information "played a significant part" in the subsequent warming of relations between the two countries, he said.

But Assistant U.S. Attorney Joseph J. Aronica characterized Chin as a man of duplicity, aptly highlighted in July 1981. On July 1, Chin was honored at CIA headquarters at Langley with the Career Intelligence Medal for his three decades of service. Just two weeks later, Aronica said, Chin met a top-level Chinese intelligence official in Hong Kong and was paid $40,000.

FBI Special Agent Mark R. Johnson, who interviewed Chin at his Alexandria apartment Nov. 22, the night he was arrested, testified that he and two other agents confronted Chin with evidence that the FBI knew of his trips to Hong Kong, Canada and China to meet with his Chinese contacts. Chin then said that he had begun passing information to the Chinese intelligence service in 1949 and that he had received about $140,000 over the years for this service, Johnson testified.

The FBI agent also testified that Chin said he had no contact with his Chinese "handler," an intelligence official named Ou Qiming, from l967 to 1976 because Ou was in prison in China. Those years include the period when Nixon's secret Chinese diplomacy took place.

Johnson said that on one trip to Hong Kong in 1983, Chin met with Ou and suggested that another CIA employe named Victoria Liu Morton, who would be traveling to Hong Kong, might be susceptible to recruitment as a spy. Ou rejected approaching Morton as "impractical," Johnson testified.

Chin "was literally stunned by the amount of detail we knew" of his Hong Kong and Peking travels, speculating that Ou had told the FBI the information, Johnson said of the interview on the night of Chin's arrest.

The whereabouts of Ou (pronounced "O") is unknown to officials.

According to papers filed by prosecutors, Chin, who had top secret and later codeword security clearances while at the CIA, told FBI agents he had been given a polygraph test only once during his CIA career and had passed the test because "the questions asked of him had been vague and not in Chinese."

He would have had more difficulty passing the test if the questions had been "more pointed" and in his native language, Chin told the agents.

Johnson testified that Chin told him that he decided what documents he would pass to the Chinese, taking them in his briefcase or coat pocket from his Rosslyn office. Once home, Chin photographed the documents with a Minolta camera and then gave the undeveloped film to a contact at a Toronto shopping mall.

After his retirement from the CIA in January 1981, Chin made up "a cock and bull story" that he had been hired by the National Security Agency to maintain his contacts with the Chinese, Johnson said Chin told him. He passed a report to the Chinese that he said came from NSA documents, but was actually based on the "Puzzle Palace," a book about the NSA, Johnson testified.

Johnson said that during the six-hour interview Chin told the three FBI agents that "when I was 6 I realized that if I learned English I could get out of China and move to the West and if I moved to the West, I could earn some money."