Abstract. Wind energy is clean and renewable, with the progress of the wind power technology, the accumulation of operation and maintenance experience, reduced generation cost, large capacity of wind farms connected to grid have been built. It is urgent to study the reactive power optimization control of the wind farm, so as to realize the wind farm and power system stability, reliable, good and economic operation. This paper established a wind farm containing 33 sets of 1.5MW double-fed wind turbines in power system analysis software package (PSASP). Through the 18 kinds of different operating types of the power flow calculation by PSASP simulation, the optimal reactive power control scheme is presented by comprehensive analysis on power flow calculation results to finish the wind farm reactive power optimization control aim. Accordingly, this paper makes a detailed analysis of the reactive power optimization control scheme, such as the choice of the compensation device, the position of the compensation and the compensation capacity, by comparing the power flow calculation results before and after the installation of reactive power compensation equipment in the wind farm, the effectiveness of the reactive power optimized control scheme is verified.