Arrested during a trip to Guangzhou in early 2005, Ching's initial trial lasted only one day. His supporters say there is no firm evidence aganst him.
China's Xinhua news agency said he was convicted of selling unspecified "state secrets and intelligence" to an unnamed Taiwanese foundation suspected of fronting espionage activities.
Hong Kong journalists allege political reasons behind Ching's detention and have held a series of a protests demanding his release.
Recent years have seen a crackdown on the media by Chinese authorities despite an opening up of the country's booming economy.
Many journalists and bloggers have been jailed on charges of violating the country's ambiguous secrecy and security laws.
In August, Zhao Yan, a researcher for the New York Times, was ruled innocent of charges of leaking state secrets to foreigners but was later jailed for three years on unrelated charges.