Abstract: With the continuous development of optical plastic molding technology, optical plastic lenses are widely used in various optical systems. Optical plastics have the characteristics of convenient mass production, high design flexibility, light weight, and high impact resistance. This study further examines the characteristics of optical plastics and analyzes the feasibility of applying optical plastics combined with the characteristics of the optical system of laser-guided weapons. Thus, an optical system was designed based on aspheric optical plastics according to the specific optical system parameters, and the spot quality of the system was analyzed to meet the application requirements. Finally, to address the problem of optical plastics being sensitive to temperature changes, the laser-guided weapon detection system was modeled using the LightTools software. The sum–difference amplitude deviation and angle deviation of the system output under different temperature environments were analyzed to further verify the impact of optical plastics on the system and determine their applicability in optical systems.