Xu Liangying, a scientist and an advocate of democracy in China who was renowned for translating the works of Albert Einstein while banished to the countryside for denouncing Mao Zedong’s purge of intellectuals, died on Monday in Beijing. He was 92.

His son Xu Chenggang confirmed the death.

In a life that spanned many of the convulsions of 20th-century China, Mr. Xu evolved from an ardent supporter of the Communist Party into an outspoken critic of the government, giving heart to the pro-democracy demonstrations of 1989 before they were crushed by the military. Threading through that life was his conviction that science, exemplified by Einstein’s achievements, offered China a beacon of reason.

“Superstition is the great enemy of truth,” he told a Chinese magazine, Caijing, last year. “We must use science and democracy to eradicate modern superstitions of every kind, to eradicate superstitions that are born of loyalty.”

Xu Liangying was born in the eastern Chinese province of Zhejiang on May 3, 1920. He entered Zhejiang University in 1939, determined, he wrote on his entrance form, to become an “authority of modern physics.” As a high school student he had read “The World as I See It,” a collection of Einstein’s essays.