Ching's family had pushed for an early release as he had been suffering from bad health.
 
He was arrested in the southern city of Guangzhou in early 2005 and his initial trial lasted just a day.
 
China's state media said he was convicted of selling unspecified "state secrets and intelligence" to an unnamed Taiwanese foundation suspected of fronting espionage activities.
 
In November 2006 an appeal against his sentence was rejected by a court in Beijing.
 
A worldwide association of writers has been urging China to release 40 jailed writers and journalists including Ching ahead of the 2008 Olympics in Beijing later this year.