A hybrid solid-state LiDAR system specifically designed for detecting rapidly rotating small celestial bodies was introduced. The ranging principle was analyzed and an imaging model was designed based on the characteristics of the fast steering mirrors and the single photon array detector. To evaluate the performance and stability of the LiDAR system in small celestial body detection, a mapping validation method based on an outdoor sandbox featuring small celestial bodies was proposed. The results show that the hybrid solid-state LiDAR system maintains high accuracy under different operating modes and power levels. In the global terrain mapping mode, the resolution is 1100×1100, and the imaging time is 0.86 s. The mapping accuracy is 2.86 cm (3σ) at a distance of 100 m. In the step-scanning imaging mode, the resolution is approximately one-seventh that of the global terrain mapping mode, and the average accuracy reach 3.10 cm (3σ) at distances between 34 and 83 m.