The development of Voltage Source Converter Based High Voltage Direct Current (VSC-HVDC) technology plays an important role in promoting intelligent power grid and integrating renewable energy to the grid. Since that the control scheme has a great influence on system performance, it needs to improve the operation stability of the VSC-HVDC system with superior control strategy with the consideration of unknown disturbances and transmission delay. This paper presents an adaptive backstepping robust control scheme to improve the dynamic response of the system during transient process, so as to improve the stable operation ability of the system. First, a mathematical model of VSC-HVDC including the unknown disturbances and transmission delay is constructed. Secondly, the adaptive law is designed to observe the integrated unknown terms of the system. Then the adaptive backstepping robust control strategy of VSC-HVDC system is designed to improve the dynamic response characteristics of the system during the transient process. The simulation model and control system of VSC-HVDC system are built on the PSCAD/EMTDC platform, and the effectiveness of the proposed robust control scheme is verified.