In the context of a high proportion of new energy power system, the randomness and volatility of new energy output and the imbalance of spatial distribution seriously affect the voltage and frequency security and stability of the power system. Aiming at the current frequency and voltage decoupling control of new energy field station may not be able to meet the demand of safe and stable operation, this paper proposes a coordinated control method of active and reactive power of new energy field station. On the basis of considering the influencing factors such as large fluctuation of new energy output of the system and dynamic behavior of the system load, the Thevenin Equivalent Parameters (TEP) identification method based on Sage-Husa Adaptive Kalman Filtering is used to correct the TEP issued by the dispatch center to obtain the accurate TEP of the system at the current moment. Based on the system TEP and network current information, the system grid voltage value is calculated under the situation of active standby transferring out or output increasing in new energy stations, and the voltage safety requirement of Point of Common Coupling (PCC) is met by coordinating and controlling the active and reactive power of equipment in the stations. The validity of the coordinated control of active and reactive power is proved by the simulation examples.