In order to provide technical reference for equipment test and assessment in the context of war preparation, in view of the complex dynamic characteristics between the fuselage-landing gear-ground of the taxiing takeoff and landing UAV during the takeoff and landing phase, this paper establishes the system dynamics simulation model and dynamic process of the aircraft-landing gear-runway, and uses the multi-scale method and the finite element analysis method to study its different aerodynamic loads The dynamic characteristics of the system under the coupling of gravity and actuator load, and the reliability and safety are simulated and analyzed. The results show that different landing speeds have great influence on the dynamic behavior of the landing gear-ground system; The strength, stiffness and safety characteristics of the landing gear system meet relevant indicators. Through the analysis of the dynamic safety characteristics of the taxiing takeoff and landing UAV and the ultimate fatigue life in flight operations, it provides a technical reference for the subsequent assessment of weapons and equipment and the evaluation of performance base.