The invention relates to a fast multispectral remote sensing polarization imager. A system can work under an active mode and a passive mode and can improve the detectability of a target by controlling the polarization state and the wavelength of incident light. The system essentially consists of an emitting part, a receiving part, a controlling part and an image processing part. The emitting partessentially consists of a multi-wavelength pulse light source, a polarization module and a beam shaping, collimating and beam expanding part. The receiving part consists of a scanning and receiving telescope, the polarization module and a multispectral camera. A control system essentially controls the polarization state of the emitting part and the receiving part and obtains images under various polarization modes. The image processing part realizes the pseudo-color coding of an intensity image and a polarization degree image. The polarization state of the incident light can be adjusted by a fast adjustable liquid crystal wave plate; imaging range is enlarged in a way of scanning and receiving; and finally the noise is eliminated by image processing, so as to realize a pseudo-color codingimage with exact real-time intensity and polarization degree.