Chen Kegui, nephew of blind activist Chen Guangcheng, is being tried in a Chinese court for assaulting local officials who were looking for his uncle.
Chen Guangcheng escaped house arrest earlier this year and then took refuge at the US embassy in Beijing.
After he fled, his relatives’ homes were raided and his nephew, Chen Kegui, was detained by police, who accused him of attacking officials with a knife.
The activist has long expressed fears his relatives would face reprisals.
In the past, China has frequently punished family members of well-known dissidents.
Chen Guangcheng’s escape caused a diplomatic crisis when it emerged that he had taken refuge in the US embassy. It was finally defused after weeks of uncertainty when Chen Guangcheng was allowed to travel to the US for studies.
After he fled from his village, which was being guarded by government-hired guards, his relatives’ homes were raided.
In an interview shortly afterwards, Chen Guangcheng’s brother and sister-in-law described being beaten by local officials.
But the authorities say that Chen Guangcheng’s nephew, Chen Kegui, hacked and wounded officials.
Family members say he acted in self-defence after the officials stormed his home and assaulted his parents.
He was originally charged with “intentional homicide” but the charge was later changed to “intentional injury”.
Human rights groups have expressed concern over whether the nephew will get a fair trial.
Chen Guangcheng, a self-taught lawyer, has campaigned against forced abortions under China’s one-child policy and was jailed for four years in 2006 for disrupting traffic and damaging property.
He was placed under house arrest after his release in 2010.
After he sought refuge in the US embassy, the Chinese authorities allowed him to leave the country with his wife and two children to study at the New York University School of Law.
In August, after meetings in the US Congress, the activist urged Washington to investigate his case and protect his family at home in China’s Shandong province.
Chen Guangcheng said Beijing had not fulfilled guarantees made to him about his own treatment and his family’s security when he left China.