Wu died yesterday morning while vacationing in Honduras with friends, the Laogai Research Foundation said in a statement.
He founded the organization in 1992 to analyze and raise awareness about China's "laogai" or forced labor detention centers, which began under Chinese revolutionary leader Mao Zedong.
While studying at university in China, Wu was sentenced to 19 years in prison after speaking out against the Soviet Union, an ally of China.
He was released in 1979 and in 1985 came to the United States, where he became a citizen and worked to raise awareness about the laogai.
Also Read
Through his foundation, he played a prominent role in pushing the US government to address human rights issues in China, frequently speaking in front of Congressional committees and meeting with prominent American politicians, including former President George W. Bush.
Wu was arrested in China in 1995 on charges of espionage in retaliation for his human rights work.
Beijing ultimately deported Wu after first sentencing him to 15 years in prison during a speedy trial a week before the meeting.
Wu, an author of multiple books, also founded the Laogai Museum in Washington, devoted to telling the story of those subjected to the system.
China has carried out some penal reforms, but Wu's foundation says that "the fundamental structure of the laogai system remains intact".
In 1994, he became the first recipient of the Martin Ennals Award -- known as the Nobel Prize for human rights, and continued to campaign against other human rights abuses, including China's forced organ harvesting and population control measures.