Most of the reactive power control of doubly-fed wind farm using the constant power factor control, doesn’t make full use of the reactive power adjustment capability of DFIG and reactive compensation equipment in doubly-fed wind farm, nor does it take the network-loss in the power collector system into consideration. This paper presents a comprehensive consideration of the characteristics of current collector systems and reactive power regulation capabilities of DFIG for reactive power control strategy,The strategy is based on the real-time monitoring date include the voltage date of Point of Common Coupling and active power output date of DFIG,according to analysis the power characteristics of DFIG and the reactive power demand of wind farm, using genetic algorithm for multi-objective reactive power optimization control model of wind farm, to reduce network-loss of the collector system and improve the power quality of the Point of Common Coupling. A simulation case of an actual wind field verifies the validity of the policy.