Muslim Uighur separatists, who Beijing says are terrorists trying to split China, have been struggling for decades for self-determination in the remote northwestern region formally established on 1 October 1955.
China says its system of ''autonomous regions'' for ethnic minorities allows them a degree of self-governance, but activists say it is a means for Beijing to maintain tight control.
"Ever since the establishment of the autonomous region 50 years ago, Uighur government workers have never had the right to make decisions. They are all made by the Han Chinese," said Dilxat Raxit, of the World Uighur Congress, a Germany-based group seeking more freedoms for the region they call East Turkestan.
A delegation of Chinese leaders, led by security chief Luo Gan, was on hand in the Xinjiang capital, Urumuqi, for anniversary celebrations that started on Saturday with a flag-raising and cannon shots.
"The unprecedented achievements Xinjiang has made in the past 50 years have proven that only by upholding the leadership of the Chinese Communist Party and taking the socialist path can there be ... happiness for Xinjiang people from all ethnic groups," Luo said at the ceremony broadcast live on state television.
Warnings of violence
Despite the gala song and dance shows aimed at showcasing ethnic unity, Luo repeated warnings of potential violence.
"We have to further ... oppose and crack down on forces of ethnic separatism, religious extremism and violent terrorism and safeguard social stability and national security," he said.
This past week, Luo told police to "prepare for danger" in Xinjiang, accusing dissidents of plotting to sabotage the celebrations.
Carpet making is a traditional
industry for the Muslim Uighurs
The United States warned American travellers ahead of the anniversary to be vigilant against "terrorist" attacks there.
The Public Security Ministry last month labelled East Turkestan forces as the main "terrorist" threat to China, and said more than 260 "terrorist" acts had been committed in Xinjiang in the past two decades, killing 160 and wounding 440.
But a report this year by Human Rights Watch said China was using its support for the US "war on terror" to justify a wider crackdown on Uighurs that was characterised by arbitrary arrests, closed trials and the use of the death penalty.
The World Uighur Congress said 1 October should be marked as a day of mourning in the region, and added that while the group did not support violence, frustration with Chinese rule was growing.
"The Uighur people in East Turkestan are in a very hopeless, desperate and frustrated situation. Continued hopelessness could lead to violence," the group said in a statement.