Abstract: In order to improve the dynamic performance of CLLC resonant converter, a control method for CLLC resonant converter based on state trajectory model is proposed in this paper. Based on the time domain model of CLLC resonant converter, the state trajectory model of the operating mode of CLLC resonant converter is established by eliminating the high frequency components of the resonant tank energy. On this basis, by simplifying the time domain equation and utilizing the geometric relationships in the state trajectory, analyzing the relationship between the energy of the resonant tank in detail, the trajectory control strategy of the CLLC resonant converter is proposed. This strategy controls the pulse width of the switch gate drive signal by the transient process load current, so that each state variable can rapidly track the theoretical trajectory. The CLLC resonant converter can reach the steady state in the shortest time after the load change. Finally, a 300 W experimental prototype was built to verify the trajectory control strategy. Compared with traditional linear control, experimental results demonstrate that the trajectory control strategy significantly improves the dynamic performance of CLLC resonant converter