The lawyer, Wu Liangshu, was beaten up by court policemen in the presence of two judges and one other official when he refused to hand over his mobile phone for inspection by police in a district court in Nanning in the Guangxi region on Friday, Hong Kong-based South China Morning Post reported.
Wu was photographed leaving the court with his shirt torn open and half of his trousers ripped away.
Agitated over the incident, over 800 attorneys have signed a petition condemning the attack.
"Without any legal stance and paperwork such as a search warrant, court policemen are not allowed to carry out such an inspection," the lawyers said in a statement.
"We are of the view that this is a classic case of abuse of power. Searching people in whatever way they please is an illegal act punishable by law," the statement added.
The lawyers also asked the court officials to release surveillance camera footage of the incident to the public.