Human Rights Watch said more than 100 trials were pushed through the court system.
"The Chinese government has refused every external request for a real accounting of the detention, arrest and sentencing of those involved with the Tibetan protests," said Sophie Richardson, Asia advocacy director at Human Rights Watch. "Both the arrests and the releases seem to have been arbitrary, and we still know next to nothing about those who are still detained or have been imprisoned."
Large-scale protests against Chinese rule erupted in Tibet last March on the anniversary of the failed 1959 uprising against Chinese rule. During the course of four days, hundreds of monks protested and rioters burned Chinese shops and government buildings and attacked Chinese-looking passersby.
The Chinese government said its crackdown amounted to a national security issue.
"The government's national security concerns do not exempt it from its obligation to respect fundamental rights and freedoms and offer equal status before the law to all its citizens, whatever their ethnicity," Richardson said.