The present disclosure provides a method for transmitting a synchronization signal (SS), the method comprising: performing a listen-before-talk (LBT) operation in a pre-defined window; if the LBT operation succeeds, transmitting an SS block (SSB) in the window, wherein the SSB comprises the SS, or the SSB comprises the SS and a physical broadcast channel (PBCH). Compared with the prior art, the present disclosure may significantly improve the efficiency of data transmission and the access performance for the communication system by relaxing the time when the base station implements the LBT, that is, allowing the base station to implement the LBT in the pre-defined window and transmit the SSB after the LBT succeeds.