| Chinese men in plain clothes, believed to be security staff, follow journalists outside Zhou's trial |
Zhou, 52, accepted the ruling and will not appeal, the official Xinhua news agency reported. His half-day trial in the northern city of Tianjin followed those of two related legal activists earlier this week, both on charges of subversion.
As with the others, Zhou was detained in July of last year amid a sweeping round-up of activists and lawyers.
About 300 of them were initially seized and questioned before most were released.
Zhou "played a major role in a group of activists who attempted to manipulate public opinion and damage national security by spreading subversive thoughts", state media quoted the verdict as saying.
It said Zhou worked with activists Hu Shigen, Zhai Yanmin and Li Heping "to encourage lawyers to highlight sensitive cases and hired protesters to disturb the judicial system".
Hu was given 7.5 years on Wednesday and Zhai a suspended three-year sentence on Tuesday, while Li is being tried separately. Zhou also "asked administrative officers in the law firm to post anti-government comments online to stir up public sentiment", the verdict said.
Zhou established Fengrui in 2007, and the following year took on one of the country's biggest dairies in a massive tainted infant formula scandal that the government had tried to squelch.
The firm has also represented clients targeted by the government, including members of the banned Falun Gong meditation sect and activist artist Ai Weiwei.