A system for synchronizing clock, which is used to realize the synchronization between a radio frequency module and a base band module in a base station, comprises: one or more time generators, located on the radio frequency module side, configured to generate a synchronous signal according to an external clock signal, and to send the synchronous signal to a time distributor; the time distributor, located on the base band module side, configured to generate a synchronous clock according to a synchronous signal from one of the one or more time generators, and to adjust the synchronous clock according to a communication delay between the time generator which outputs the synchronous signal and the time distributor, and to send the synchronous clock adjusted to the radio frequency module and the base band module to realize the synchronization between the radio frequency module and the base band module.