John T. Downey, who prepared for Harvard Law School by spending 21 years in a Chinese prison, graduated from the school last spring and now lives quietly as a small-town lawyer.

Shot down while flying over the People's Republic as an agent of the Central Intelligence Agency (CIA) in 1952, Downey is now busy learning the ins and outs of "general practice" law, he said last week, and shunning publicity.

Downey's law firm in Wallingford, Conn.--his home town--recently changed its name from Carrozzella and Richardson to Carrozzella, Richardson and Downey.

The Chinese released Downey in March 1973 after President Nixon admitted that the American was a CIA agent. The United States maintained for years that Downey was a civilian employee of the U.S. Army, and in 1954 the Defense Department said Chinese accusations of espionage against Downey "illustrate again the bad faith, insincerity and amorality" of the Chinese government.

Downey was chained in leg irons until he provided his captors' information about the CIA, and he then spent another 14 months in solitary confinement. United States officials have never revealed the nature of Downey's mission in China, but Chinese officials said in 1954 that Downey had been trying to get supplies to a spy ring he was organizing within Chinese borders.

The People's Republic arrested nine citizens of Nationalist China at the same time as Downey and accused them of taking part in the spy ring.

Downey said last week he does not like to discuss publicly the CIA, China or the years he spent there. The federal government no longer is in touch with him. Downey added, and although he receives occasional lecture invitations, he always "politely declines."

Harvard Law School is a "great place," Downey said, adding, "unlike a lot of my classmates, I enjoyed my three years tremendously."