As an important optical element which can change the polarization state of incident light and produce phase delay,wave plate has been a hot research topic for its accurate and rapid measurement.To solve the problem of insufficient sensitivity and slow speed of wave plate parameter detection,a simple method based on photo elastic modulator(PEM)and electro optic modulator(EOM)for simultaneous measurement of phase retardation and fast axis azimuth angle of wave plate is proposed.In this method,one reference optical path is used to monitor the phase retardation of the PEM to achieve phase stabilization control,and the other optical path is used to detect the parameters of the wave plate to be measured while maintaining the PEM stability.The double frequency component and the direct current component of the detection signal are extracted based on FPGA and digital phase locked technology,and the data processing is realized in the on chip programmable system,thus the phase retardation and fast axis azimuth angle of the wave plate are detected with high speed and high precision.The experimental results show that when the PEM phase retardation is stable at 2.405 rad,the average relative deviation of phase retardation and fast axis azimuth angle of the system is 0.27% and 0.25% respectively.The measuring process is simple and quick,and the measurement accuracy is high.