Based on the characteristics of automatic generation control（AGC）unit response and the AGC strategy of North China Grid，the evaluation method of AGC regulation efficiency based on phase measurement unit（PMU）data is proposed.The wide area measurement system（WAMS）data of unit output and AGC order is used to identify the regulation process and calculate the index of unit efficiency.The method suggests an effective solution to the communication delay and the limitation that supervisory control and data acquisition（SCADA）system data cannot accurately describe the power units fast changing process.And the program system using PMU millisecond sampling data on the AGC performance test is developed.The method and the software have been put into actual operation，the calculation results show that the new method is more accurate and practical.