The Central Military Commission (中央军事委员会) refers to one of two bodies within the People's Republic of China. Unlike most national armies, the People's Liberation Army is not considered as just another ministry. Although China does have a Ministry of National Defense, headed by a Minister of National Defense, it exists solely for liasion with foreign militaries and does not have command authority.
These two bodies are in command of the People's Liberation Army (including the People's Liberation Army Navy and air force) and have overlapping positions. There is the state CMC and the Party CMC. The state CMC theoretically reports to the National People's Congress but is in practice autonomous. The Party CMC by contrast is subordinate to the Politburo of the Communist Party of China. Therefore under ordinary conditions, the General Secretary of the Communist Party of China commands the Party CMC which then issues policy directives to the State CMC which then commands the armed forces. The post of the state CMC was created to form the illusion that the military, like most countries, was under the command of the state instead of the party. In actuality, the party and the state CMC have identical top leaderships. Power is wielded through the party military commission, but legitimacy arises from the state CMC.
The chairman of the CMC and one of the vice-chairmen are always civilians and a top party member. The remaining members are military officers. The Chairman of the CMC is often a senior official who has given up his other posts, and the CMC Chairman was held by both Deng Xiaoping and Jiang Zemin after given up their other posts.
Along with posts of General Secretary and Presidency, the Chairmanship of the Central Military Commission is the third crown in the Chinese political realm. It can allow for semi-retired leaders to pull string behind the scenes.
During periods of political stress such as the Tiananmen Protests of 1989, this system can act in an altogether different way. During those protests, the President of the People's Republic of China Yang Shangkun was able to cooperate with the Chairman of the CMC Deng Xiaoping to effectively overwhelm Party General Secretary Zhao Ziyang.
There was speculation that Jiang Zemin would be able to retain some authority after his retirement from the positions of General Secretary and President however this does not appear to be the case. One major factor, which went unnoticed by many analysts, is that in contrast to Deng Xiaoping who always had close relations with the People's Liberation Army, Jiang has no military background. In addition, with the promotion of the fourth generation of Chinese leaders to lead the civilian party, there was also a corresponding promotion of military leaders, and all of the military members of the CMC come from Hu Jintao's generation rather than from Jiang's.