Supercooled water in the cloud is a key factor of weather modification, and the supercooled water detection technology and equipment employed on unmanned aerial vehicle (UAV) platforms are of great significance for weather modification. A compact polarization LiDAR operating at 1 064 nm wavelength was introduced, which could identify water clouds by measuring the depolarization ratio of the scattered echo signals, and the detection of supercooled water clouds was realized by combining the height of the zero degree isotherm. The main technical parameters and composition of the LiDAR system were introduced, and its miniaturized, lightweight and high-reliability design could be mounted on the UAV to detect the spatial distribution of supercooled water. An improved rotating waveplate method was used to accurately calibrate the depolarization ratio of the LiDAR, and its accurate measurement was achieved, which was the key to effectively detect supercooled water. The observation experiments with high temporal and spatial resolution were carried out on the ground to simulate and verify the detection ability of the LiDAR on the UAV platform. The results show that the proposed LiDAR has the ability to detect supercooled water in the cloud on the UAV platform, and can provide important supercooled water distribution information for weather modification.