Based on its ability to provide synchronous AC power support for passive grids, Voltage Source Converter based High Voltage Direct Current (VSC-HVDC) is gradually becoming the preferred solution for long-distance offshore wind farm integration. It focuses on the grounding method of VSC-HVDC used for offshore wind farm integration. Firstly, several grounding methods of converter stations in the existing engineering are compared and analyzed, and the advantages and disadvantages are described. Then the structure and control strategy of VSC-HVDC for offshore wind farm integration are introduced. And three grounding methods for converter stations suitable for this situation are proposed. Finally, for a domestic planned offshore wind farm, a simulation model of ±320 kV/1 100 MW MMC system is built in the electromagnetic transient simulation software PSCAD/EMTDC. The fault scanning of MMC system is carried out based on the simulation model and the overvoltage characteristics of the system under three grounding methods are compared and the results show that VSC-HVDC in the three grounding methods have similar overvoltage characteristics. The research results of this paper fill the gaps in related research fields and provide reference for domestic offshore wind farm integration projects in future. This work is supported by National High-tech R & D Program of China (863 Program) (No. 2012AA051704).