A wave plate is commonly used for polarization measurement and polarization calibration of a large solar telescope. In this study, we developed a measurement system based on the dual-beam polarization analyzer configuration to measure the phase retardance and azimuth angle of the wave plate, and derived the corresponding mathematical model. The influence of azimuth error of the polarizer in the single beam measurement system was overcome by fitting the azimuth of the polarizer. At the same time, we analyzed the retardance range of the measuring plate, and accurately measured the wave plate used in polarization calibration and polarization measurement. Finally, we analyzed the main error sources of the system, including the power noise of the light source, position error of the rotating stage, and nonlinear response of the detector. Subsequently, we corrected the detector's nonlinear response after calibration. The measurement errors of phase retardance and azimuth angle are within 0.02° for a quarter-wave plate and a wave plate with phase retardances of 127°. The retardance and azimuth errors are less than 0.05° for the wave plates with phase retardances of 27°--145° and 215°--333°.