To guarantee the measurement accuracy of the space-borne imaging spectrometer, the dual Babinet compensator pseudo-depolarizer (DBCP) is designed. The principle of the DBCP is analyzed by utilizing the electromagnetic wave theory and light wave transmission theory, and a suitable wedge angle of the DBCP is schemed out based on the formula of polarized light propagation in birefringent crystal. The depolarization performance of the DBCP is worked out with a set-up polarization testing device. The results show that the DBCP has a better depolarization performance within the incidence angle range of -15～15 ℃. When the wedge angle is 6°, the depolarizer can realize depolarization at detection band with degree of depolarization better than 99%. Which is independent of the azimuth angle and frequency, and without affecting the imaging quality. Furthermore, the DBCP has many advantages, such as high degree of depolarization, high transmittance, stable performance and small volume. The uncertainty of measurement is 0.00290, because of the systems error.