PWM inverter, as the main part of wind power grid-connected system, directly determines the quality of the power sent finally to grid. It has become the focus of research to develop a high-performance inverter control system. Based on the analysis and establishment of the mathematical model of the grid inverter system, the vector control strategy based on the voltage directional technique is analyzed in this paper. It consists of two closed loops. The fluctuation of direct voltage is suppressed due to the existence of voltage outer loop. Current inner loop realizes the independent control over meritorious electric current and reactive current through the feedforward of grid voltage and the decoupling of grid-connected current, which makes the inverter power factor close to 1.