The trials are expected to start this week in the capital of the Xinjiang Uygur autonomous region in Northwest China.
The arrested face charges such as: vandalizing public property, organizing crowds to cause bodily harm to others, intentionally causing bodily harm to others, robbery, murder, arson, vandalizing public transport, and organizing crowds to disrupt public order and traffic.
China Daily quoted an Urumqi procuratorate official, as saying that most of the arrests were made in Urumqi and Kashgar, a southern Xinjiang city with a heavy concentration of Uygur people.
According to police, 718 people had been detained for taking part in the July 5 riot, in which 197 people were killed and more than 1,600 injured.
During the riot, predominantly Uygur rioters armed with batons and bricks smashed shops and vehicles while beating passers-by, after a protest against attacks on Uygur workers at a factory in South China in June.
Two days later, some Han people retaliated against the Uygurs.
Local police had gathered more than 3,000 new items of evidence to be used during the trials.
Blood stained bricks and clubs,91 video clips and 2,169 photgraphs were retrieved from 3,318 items collected.