Abstract: According to the property of low-light-level (LLL) imaging system, the LLL panoramic imaging system was designed, which was made up of a reflection part and a transmission part. The basic theory for designing the reflection part was expounded, and according to the theory, a imaging system of good performance was designed and optimized. This system has a waveband of 0.4 m~ 0.9 m, an effective focal length of 2.43 mm, a working F-number of 1.5, and a field of view of 30～100. Simulation results show that in the entire field of view, the distortion is less than 6%, the value of the modulation transfer function (MTF) at 24 lp/mm is greater than 0.3. The system can meet the demands for imaging.