The state estimation based on the synchronous phasor measuring unit (PMU) is the wide-area measurement system (WAMS) of important technical support, It is great to real-time monitoring of large area power grid control direction and provides advanced information technology platform. it provides advanced information technology platform for real-time monitoring of large area power grid and control direction, but the current wide-area measurement system less point, difficult to direct the system state estimation. This paper proposes a method based on PMU and SCADA mixed measurement state estimation. The simulation results show that this method has a higher convergence speed, And from the topology of the network structure of the restrictions.