Time synchronization method between direct-communication UE (user equipment) and UE

An embodiment of the invention discloses a time synchronization method between direct-communication UE (user equipment) and UE. The method comprises the steps as follows: when first UE and second UE build a direct-communication link, a configuration parameter sent by a base station is received, wherein the configuration parameter comprises a second time-frequency resource position where the second UE sends a detection signal; a second detection signal sent by the second UE is obtained according to first downlink fixed time between the first UE and the base station; the second detection signal is detected through correlation of the signals to obtain a first time deviation; time synchronization of the first UE and the second UE is performed according to the first time deviation. Data transmitting fixed time of the UE at the transmission end between the direct-communication UE is adjusted through the detection signals between the direct-communication UE so as to keep consistent with data receiving fixed time of the UE at the receiving end, data can be transmitted regularly and synchronously between the direct-communication UE according to adjusted time, the data transmission accuracy between the direct-communication UE is guaranteed and the frequency utilization efficiency of the system is improved.