Aiming at the requirements of high antioverturning and maneuverability of some vehicleborne radar, a hydraulic automatic leveling system project based on the combination of frog legs and leveling legs is adopted. Mathematical model of vehicle leveling was established, and a new load calculation method of the leveling leg load during the leveling process was proposed. Based on it, the frog legs and leveling legs structure design was completed and verified by using the finite element method (FEM). Comparison between the leveling system test and the calculated data was done. Result shows that the automatic leveling system meets the predetermined requirements and provides an important reference for subsequent similar product design.