Abstract: Low-illumination night vision equipment based on complementary metal-oxide-semiconductor (CMOS) devices has good concealment and lower cost than infrared thermal imaging equipment. It is an important means to expand human visual perception under low illumination conditions and widely used in military and civil fields. In order to meet the requirements of equipment maintenance and support under low illumination condition at night, an optical system of night vision goggle with large field of view and low illumination was designed. By selecting the appropriate optical glass material, it had a good spectral response in both visible and near infrared bands. The designed eyepiece with large relative aperture had a field of view angle of 74.46°, focal length of 46 mm, F number of 1.2, distortion less than −7.14%, total length of the system less than 80 mm and lens weight less than 100 g. Under the spectral range of 486 nm~950 nm, the eyepiece can meet the maintenance, training and scene observation without lighting at night, which provides a new technical means for the development of optical module of low-illumination night vision head-mounted system.