A synchronous soft-start networking control strategy of EMU parallel auxiliary converter is disclosed. When that first auxiliary converter is put into bus bar, the non-first auxiliary converter synchronously completes networking and network connection during the first amplitude soft-start process. The specific scheme is as follows: fast networking logic, busbar fast tracking logic and PQ droop control strategy. The fast networking logic includes the identification of the first and non-first auxiliary converter, the busbar fast tracking logic includes phase, frequency and amplitude tracking, and the PQ droop control strategy includes the introduction of correction factor K. A synchronous soft-start networ control strategy of auxiliary converter of EMU can realize fast and reliable automaticnetwor of auxiliary converter in EMU emergency traction mode. In the normal mode of EMU network, the networking time can be significantly shortened. Therefore, the invention can ensure that the EMU can be started in a prescribed time under various working conditions, and provides a powerful guarantee for the stable and reliable operation of the EMU.