See link for picture and more...
Electrical Plug/Outlet and Voltage Information for China
•Voltage: 220-240 Volts (U.S./Canada are 110-120 Volts)
•Primary Socket Types: Chinese Grounded, Chinese Non-Grounded
Others sometimes found: British BS-1363
•Multi-voltage appliances (laptops, etc.): Plug adapter
Click socket type links to view adapter for that type
•110-120V electronics: Plug adapter + step-down transformer
•Hair dryers, curling irons, etc.: Plug adapter + voltage converter
There are two official standards for plugs and sockets in the People's Republic of China. The first is the grounded, three-blade CPCS-CCC which is practically interchangeable with the type of socket found in Australia. Their non-grounded two-blade standard is very much like a 2-blade North American/Japanese plug, but the sockets generally will not accept U.S. plugs because the sockets are non-grounded and non-polarized. An adapter will probably still be required for that type. Due to a substantial Hong Kong presence in mainland China, some buildings are wired with British BS-1363 sockets, which is the primary socket type used in Hong Kong. If your appliance's plug doesn't match the shape of these sockets, you will need one or more travel plug adapters in order to plug in. Travel plug adapters simply change the shape of your appliance's plug to match whatever type of socket you need to plug into. If it is crucial to be able to plug in no matter what, bring an adapter for all three types.
•Adapter for "Type I" Chinese CPCS-CCC
•Adapter for "Type A" Chinese Non-Grounded Class II
•Adapter for "Type G" British BS-1363
But the shape of the socket is only half the story!
Electrical sockets (outlets) in the People's Republic of China usually supply electricity at between 220 and 240 volts AC. If you're plugging in an appliance that was built for 220-240 volt electrical input, or an appliance that is compatible with multiple voltages, then an adapter is all you need.
But travel plug adapters do not change the voltage, so the electricity coming through the adapter will still be the same 220-240 volts the socket is supplying. North American sockets supply electricity at between 110 and 120 volts, far lower than in most of the rest of the world. Consequently, North American appliances are generally built for 110-120 volts.
But that doesn't mean that your specific appliance isn't already compatible with the higher voltage -- it may very well be.
Laptop computer: Usually 100-240V, 50/60Hz, auto-switching. A travel plug adapter works just fine all by itself.
Desktop computer: Usually switchable between 110-120V and 220-240V via a small switch on the back of the computer, near the cooling fan. A travel plug adapter will work fine as long as the voltage switch is set to the proper position.