The invention discloses a unified transformer substation secondary equipment synchronizing device time setting method, which comprises the following steps that 1, external time setting signals are modulated into signals capable of being received by an FPGA (field programmable gate array), and the signals are sent into the FPGA to be processed; 2, the resolved timing mode is told to the FPGA in the initialization process by a time setting receiving plug-in; 3, the FPGA resolves the received time setting signals by the FPGA according to different time setting modes; after the resolving, the time setting information is transmitted onto a time setting bus of a synchronizing device; 4, all plug-ins of the synchronizing device take time setting information on the time setting bus to realize the time synchronism of all plug-ins of the synchronizing device; 5, when external time setting is interrupted, the time stored by a time setting chip can be sent to the time setting bus to realize the time synchronization of the synchronizing device. The unified processing of a source of the time setting of the synchronizing device can be realized; in addition, all of the plug-ins of the synchronizing device can synchronously obtain the time setting information; the excessive relying of non-receiving time setting plug-ins on the time setting receiving plug-pins is avoided; the universality is realized.