He had been found guilty of "picking quarrels" and "inciting ethnic hatred" after a series of social media posts, and stood trial
in Beijing last week.
Lawyer Shao Baojun said that Pu would go home and rest after nearly 20 months in detention. He said he would not appeal the verdict.
"We of course hoped he would be acquitted of the charges, but we knew the chance was slim," he said.
The U.S. Embassy in Beijing said on December 13 that the charges were "vague" and Pu "should not be subject to continuing repression."
According to his indictment, Pu made seven comments on the Twitter-like Weibo platform between July 2011 and May 2014 -- three criticized government officials and a pro-government author, while the rest were critical of Chinese policy in ethnically-divided Tibet and Xinjiang.
Amnesty International said that while Pu was unlikely to spend another night in jail, the verdict would effectively prevent him from practicing law again.
"He is one of China's most courageous defenders of the right to freedom of expression, and he's been persecuted for simply exercising that right," it said.
'I'm not radical'
Pu took part in the student-led demonstrations in 1989 that ended in a bloody military crackdown on June 4 of that year. He later become one of the best-known lawyers in China for defending human rights in courts as well as in the media.
Pu, 49, was detained in May 2014 and formally arrested the following month after attending a low-key seminar in a private home to mark the 25th anniversary of the Tiananmen Square massacre.
The state-run Global Times newspaper said in an editorial at the time that he had crossed "a legal red line" by associating himself with a topic still considered taboo in China.
Although his work has often put him at odds with the ruling Communist Party, Pu dismissed the risks in a 2013 interview with CNN.
"I think I'm fine," he said. "I'm a moderate, and the government has treated me well. I'm a veteran lawyer and haven't made mistakes in my career. I'm not radical, and I don't threaten the government."