The convictions and sentences were handed down on Friday by the Intermediate People's Court in Kunming, in the southwestern province of Yunnan, state broadcaster China Central Television (CCTV) reported on a verified microblog.
The March 1 carnage at a train station in Kunming also saw more than 140 people wounded and was dubbed "China's 9/11" by state-run media.
The suspects, whose names appear to identify them as members of the Uighur minority, had been accused of crimes including "leading a terrorist group" which planned and carried out the attack, Kunming's Intermediate Court said earlier on its microblog.
Four armed guards in helmets and dark clothing, and holding automatic weapons, were positioned inside the courtroom opposite the suspects, CCTV showed.
The accused - three of them men with shaved heads, the other one a woman - wore prison clothes. Each of them had a separate dock, with two police officers sitting behind.
More than 300 members of the public were present in court, Xinhua said, including some victims and their relatives.
Beijing blamed the attack on "separatists" from the resource-rich far western region of Xinjiang, where at least 200 have died in attacks and clashes between locals and security forces over the last year.
The Kunming mass knifing was the biggest-ever violent incident against civilians outside the region.
