In view of the disadvantages of traditional double closed-loop vector current control (VCC), such as slow dynamic response, pool decoupling performance and high current harmonic distortion, a transient mathematical model for the VSC-HVDC system in d-q synchronous reference frame was developed. Then, a double integral sliding mode direct power control strategy (DISM-DPC) combining the features of direct power control (DPC) and integral sliding mode control (ISMC) was proposed. Double integral sliding mode decoupling based on the deviations of instantaneous active and reactive power were designed, and the corresponding control laws were derived. Finally, the simulation model of the system was established by PSCAD/EMTDC, and the results show that the method can achieve power decoupling, improve the dynamic and static quality and robustness of the system with simple algorithm, and effectively reduce chattering caused by switching action.