According to the wind farm grid connected voltage source DC transmission system, the discrete mathematical model VSC-HVDC system inreference frame is derived. A novel direct power control strategy in the voltage sourced converter is proposed based on instantaneous power theory and space vector pulse width modulation in the paper. Constant active and reactive power controller is used in the wind farm side; a constant DC voltage and constant reactive power controller is used in the grid-side. A case of two-terminal VSC-HVDC system for grid connection of wind farms is developed in Matlab/Simulink. The simulation results show the effectiveness and feasibility of the proposed control methods which provide a viable solution in voltage sourced converter based high voltage direct current systems for offshore wind farm.