Dual-bridge series resonant converter (DBSRC) under discontinuous conduction mode (DCM) can greatly improve the efficiency under light load and achieve wide voltage gain range. However, when the transmission power command is changed abruptly during the control process, a transient process will appear in the resonant cavity, which limits the converter’s control performance. This paper analyzes the phenomenon and points out the mechanism of transient bias. On this basis, a transient control strategy is proposed for the transient process under DCM, which eliminates the transient process within half a switching cycle and greatly improve the control performance for DBSRC. Finally, the performance of the proposed control strategy is verified by simulation and experimental results.