To solve the voltage instability issue caused by large-scale wind farm integration，the characteristics of multiple reactive power sources in both time-scale and space-grain-size aspects are analyzed，and a reactive power and voltage control strategy is proposed to coordinate the wind farm substation central compensation devices and doubly-fed induction generator（DFIG）.The strategy is based on the real-time monitoring data，and the interior point filter algorithm is used to solve such a multi-objective optimization model.Besides binding the voltage of the point of common coupling of wind farm to the reference value given by the higher level control，the coordinative strategy gives priority to the reactive power output of DFIG to ensure the dynamic compensation devices have enough reactive power reserves and equalise voltage reserves among all the controlled DFIGs.The simulation results of a wind farm in North China validate the proposed model and strategy.