Abstract: A polarization-type laser detection system is provided, which is capable of distinguishing between a reflected light signal from a target object and a back-scattered light signal from a mass of suspended particles in the air. This allows the laser detection system to be reliably operable under bad weather conditions when the air is filled with suspended particles. The laser detection system includes a laser means for producing a linearly-polarized laser beam which is the directed to a specified direction for target detection. When echoed back, the echoed signal is first polarized by an analyzer lens into a direction that is perpendicular to the direction in which the emitted laser beam is polarized. Further, a Fresnel lens is used for focusing the emerging light from the analyzer lens into a focal point where an optical detection module is mounted.