the control system of the VSC-HVDC is one of the most important ports of the Flexible HVDC. Most researchers are mainly focus on the design of controllers and the control methods of VSC-HVDC and pay less attention on the control system structure of VSC-HVDC. Based on the introduction of the of the basic control functions of the control system of VSC-HVDC, this paper establish a five layer control structure of the control system of VSC-HVDC including the DC system control layer, pole control layer, converters control layer, valves control layer and separate control layer. After emphasizing the necessity to adopt hierarchical control architecture, the paper describes the control functions and scope of each control layer at details, the relationship between the layers. By setting a preparatory scheme to realize the whole process of the control system, it provides reference for the software implementation in the VSC-HVDC control system.