One other person was given life in prison for the "violent terrorist attack" that killed two tourists last October, said state broadcaster China Central Television (CCTV), citing the Intermediate People's Court in the Xinjiang capital Urumqi.
The three sentenced to death were convicted of "organising and leading a terrorist group and endangering public security with dangerous methods", according to the official Xinhua news agency.
Four other people were given prison terms ranging from five to 20 years, Xinhua said.