Han Chinese workers accused the authorities of failing to protect them
China has replaced the most powerful official in its western region of Xinjiang, where ethnic violence left nearly 200 people dead last July.
Wang Lequan, who had served as secretary of the Communist Party in Xinjiang since 1994, was replaced by Zhang Chunxian, state media say.
Mr Wang was appointed to a new post in the Chinese Communist Party.
No reason was given for the move but analysts note there was much public anger over his handling of the riots.
China reported that most of the those killed in the riots were from the Han Chinese community. Order was only restored after soldiers were deployed to the region's main city, Urumqi.
Separatist militants from Xinjiang's mainly Muslim Uighur community have been waging a campaign against Beijing for independence, fuelled by resentment at the mass migration of Han workers to the region in recent years.
Since the 9/11 attacks on the US, China has increasingly portrayed the separatists as auxiliaries of al-Qaeda.
Wang Lequan incurred the anger of fellow Han Chinese in Xinjiang
As secretary of the regional Communist Party, Mr Zhang, 57 next month, becomes the most powerful figure in Xinjiang.
Previously he served as secretary of the party's committee in the southern province of Hunan.
The change at the top in Xinjiang followed a politburo meeting on Friday at which Chinese leaders reaffirmed their desire to develop Xinjiang economically, improving the living standards of various ethnic groups and ensuring long-term social stability.
Mr Wang, 65, was appointed deputy secretary of the political and legislative affairs committee of the Chinese Communist Party's Central Committee.
A career party functionary with close links to President Hu Jintao, Mr Wang he took measures in the 1990s that angered Xinjiang's Uighurs, including a switch to Chinese-language teaching in primary schools and a ban on civil servants wearing beards, headscarves and observing the Muslim fasting month of Ramadan.
He also presided over a crackdown on Uighur separatists in 1997, seeking to link them to al-Qaeda. Mr Hu appointed him to the Politburo in 2002, with special responsibility for ethnic minority affairs.
Mr Wang developed Xinjiang's economy, in particular the oil industry, encouraging the settlement of Han workers from elsewhere in China.
Last September, thousands of angry Han Chinese took to the streets of Urumqi to demand his removal and better security after the July riots and a spate of assaults using hypodermic needles.
The regional police chief and the Communist Party secretary of Urumqi were sacked after the protests.
It was, correspondents say, a rare public challenge by Han Chinese to the ruling Communist Party in the region.