The electrical current in China is 220 volts. China uses both a 2 and 3-pin power outlets.
Most hotel rooms have two electric outlets in the bathroom -- one at 110 volts and the other at 220 volts. Do keep in mind that not all outlets marked at 110 volts are marked correctly. If you have any doubt, ask the housekeeping department for a converter.
For your convenience, it is recommended that you bring your own adapters. Some hotels do provide adapters. But to be safe, bring your own.