A method and a device for initial synchronization between D2D terminals are used to implement initial synchronization between the D2D terminals. A D2D master terminal measures a time-frequency resource set used to transmit a synchronization signal, and reports a measurement result to a network device; the D2D master terminal receives a synchronization resource that is allocated by the network device to the D2D master terminal according to the measurement result reported by the D2D master terminal; and the D2D master terminal sends the synchronization signal according to the synchronization resource allocated to the D2D master terminal.