Abstract: In order to meet the measurement requirements of optic polarization characteristics, a set of laser polarization degree measuring instrument was designed. The device modulated the light wave by using a rotating 1/4 waveplate, and the degree of polarization (DOP) of light source was obtained by Fourier analysis of the modulated signal.The DOP of polarimeter was calibrated by measuring the optical power. The experimental results show that the developed laser polarimeter has a measurement accuracy better than 0.5%, which can satisfy the needs of high-precision laser DOP measurement.