Large-scale off-shore wind power generation is the hot spot in the field of wind power,and this paper studies the grid integration of off-shore wind farm based on the technology of VSC-HVDC.On the basis of the in-depth understanding of the working principle of VSC-HVDC,it puts forward a set of offshore wind power DC transmission system,sets up the system simulation model in the MATLAB/SIMULINK,and studies the system response characteristics in the steady state and typical fault condition.The simulation results show that the proposed design can effectively realize the offshore wind farm power transmission.