They were among 81 people convicted, in 23 cases, on charges that included murder and arson relating to organizing and participating in terrorist organizations, Chinese state television said.
Officials have blamed militant ethnic Uighurs for violent incidents across the country, including a car attack on pedestrians in Beijing's Tiananmen Square that killed five people, and explosions in Urumqi and Kunming railway stations.
Earlier, 29 people described as "terror suspects" were held in the city of Urumqi on charges that included separatism and ethnic hatred.
The convictions Thursday come as a security crackdown, described by Chinese authorities as a "year-long campaign against terrorism" began, provoked by an attack by five suicide bombers at an Urumqi market which killed 39 people.
Last week, 55 people were sentenced for terrorism, separatism and murder in Xinjiang.