A vehicle-mounted infrared lens was designed based on 324×256 uncooled detector. The operating wavelength range of the lens is from 8 μm to 12 μm, the effective focal length(EFL) is 9 mm, the F number is 1.3, and the field of view(FOV) is 33.26°×26.28°. The proposed lens was designed as a combination of two singlet lenses fabricated with the novel chalcogenide glass material Ge28Sb12Se60 and two singlet lenses fabricated with conventional infrared materials Germanium(Ge) and Zinc Sulfide(ZnS). Utilizing the differences in the thermal-optical properties of the utilized infrared materials, an athermalized optical design was realized by carefully adjusting the optical powers of the four singlets. Moreover, taking advantage of the superior property of chalcogenide glasses for molding preparation of aspherical surfaces, the imaging quality of the proposed lens could be further improved by introducing one aspherical surface on one of the chalcogenide glass singlets. The imaging quality of the proposed lens is close to the diffraction-limited system for the designed spectral range and for the temperature range from -40 to 60 ℃.