The defendants, who appeared to be from the region’s Muslim Uighur community, were presented at a venue holding about 7,000 spectators.
Three of the defendants were sentenced to death.
Chinese officials have blamed militant Uighur groups for a growing number of violent attacks across the country.
Photos from the open-air mass sentencing showed police trucks parked near a running track.
Prisoners wearing orange vests stood in the back of the vehicles, surrounded by armed guards, their heads bowed.
The announcement came after 39 people were killed last week when five suicide bombers attacked a street market in Urumqi, Xinjiang’s capital.
Beijing has blamed this – and other recent mass-casualty attacks – on Uighur separatists.
These include an attack in Beijing, where a car ploughed into pedestrians in Tiananmen Square, killing five people, and attacks at railway stations in Urumqi and Kunming.
China says it is pouring money into the Xinjiang region, but some Uighurs say their traditions and freedoms are being crushed.