Xinjiang is the traditional home of Muslim Uighurs, who speak a Turkic language, and China has attributed attacks there to Islamist separatists it says seek to establish an independent state called East Turkestan.
Exiled Uighur groups and human rights activists say the government's own repressive policies in Xinjiang have provoked unrest, an accusation Beijing denies.
Three of the executed group "masterminded" the October 2013 attack in the heart of the Chinese capital, official news agency Xinhua said. Five people were killed and 40 injured in the incident, when a car ploughed into a crowd in the square and burst into flames.
The other executions, carried out in recent days, were punishment for crimes ranging from setting up a terrorist outfit and illegally making explosives to attacking police officers and killing government officials, Xinhua said.
The World Uyghur Congress, the largest group of exiled Uighurs, said the executed individuals had paid a heavy price but the root causes of the issues were being overlooked.
"The lawyers, to accomplish political ends, led them to accept China's charges, and skirted the causes of the issue," spokesman Dilxat Raxit told Reuters in an email yesterday. "It's a typical case of the law serving political ends."
A report by China Central Television showed images of police leading into court, and questioning, the individuals who have been executed. It also showed footage of the Tiananmen attack, with a car being driven into the square.
Some of the people executed were blamed for attacks in Xinjiang's prefecture of Aksu, the city of Kashgar and the town of Hotan, Xinhua added.
China has been cracking down on violent crime after a string of deadly attacks in Xinjiang, executing 13 people in June.