In order to study the influence of the analyzer angle of polarization detection system on the backscatter characteristic of optical pulse in the backward detection device of optical pulse underwater, firstly, the depolarization by scattering was analyzed qualitatively when polarized light travelled in the water using the reflection and refraction theory on the scattering interface. Secondly, with linear polarized laser pulse as incident light, backscatter signals of optial pulse were detected experimentally at different analyzer angles. Finally, after comparing statistical average of leading edge, trailing edge, width, peakvalue, shape and area of optical pulse′s backscatter signal at different analyzer angles, the influence of analyze angle on the backscatter characteristic of optical pulse was analyzed. The result shows that, with the increase of analyzer angle, the backsctter singal′s width becomes narrow, the shape becomes gentle, the peakvalue and area are decreased. The leading edge and trailing edge move backward and the moving distance of leading edge is much larger than that of trailing edge. And the backscatter signal from nearby water area is restrained more effectively by the polarization detection system.