To ensure the stable operation of unmanned aerial vehicle water depth detection LiDAR under different working conditions, a LiDAR heat dissipation structure designed by combining optical, mechanical, and thermal integration analysis is proposed. The design helps achieve temperature control under different working conditions. The heat dissipation structure is designed such that it fully integrates the environmental conditions during the operation of the drone. Firstl, a thermal analysis model for the laser radar system is established using Icepak. Then, Ansys is used to perform thermal mechanical coupling analysis on the optical structure. Next, the optical system structure deformation is imported into Zemax to calculate the modulation transfer function (MTF) curve of the system through the optical mechanical interface Sigfit. Finally, the heat dissipation structure is further optimized based on the imaging quality. The experimental analysis results indicate that the temperature of each module remains within the allowable range under different operating conditions. After optimizing the heat dissipation structure, it is observed that the MTF value of the optical system is greater than 0.285 at an ambient temperature of 40 ℃, and the MTF of the optical system is greater than 0.25 at normal operating temperatures, indicating good imaging performance of the system. The results of the field experiments verify the accuracy of the optical mechanical thermal integration analysis and also indicated that the receiving optical system can achieve echo reception. In summary, the heat dissipation structure designed in this article can integrated in unmanned aerial vehicle water depth measurement LiDAR systems to ensure the stable operation of the system.