The present invention relates to a synchronization signal transmitting device, method thereof and a power electronic apparatus with the device. The synchronization signal transmitting device comprises at least one serial differential signal transmitter for receiving an identical-period pulse signal and outputting a differential signal pair, at least one serial differential signal receiver for receiving the differential signal pair and outputting a single-ended signal, and at least one controller for receiving the single-ended signal. Moreover, the controller is configured for conducting a signal filtering process and/or a signal reconstruction process to the single-ended signal, so as to obtain a synchronization signal. Thus, the present invention shows the advantages of transmission and process purely by hardware without participation of software, without occupation to calculating ability of processors, high time accuracy, and low time delay. The method and device can not only transmitting the identical synchronous clock signal with power frequency, but also the PWM carrier synchronous clock signal with high frequency ranged from several kHz to hundreds kHz.