Synchronization method and system for TDD (Time Division Duplexing) system

The invention discloses a synchronization method and system for a TDD (Time Division Duplexing) system. The method comprises the following steps: acquiring switching information for switching an uplink and a downlink generated by a near-end unit in the TDD system through a synchronization algorithm; mapping the switching information into a switching data block, and transmitting the switching data block to a remote unit in the TDD system; and acquiring the switching information from the switching data block through de-mapping, and implementing synchronous switching of the uplink and the downlink in the remote unit. Through implementation of the synchronization method and system for the TDD system disclosed by the invention, hardware such as a control logic and a filter circuit for generating synchronization signals in the remote unit can be removed while synchronous switching of the uplinks and downlinks of the remote unit and the near-end unit in the whole system is implemented accurately, and the cost is reduced.