To improve the shock absorbing performance of UAV landing gear, dynamic analysis and optimization for a cushioning mechanism of articulated landing gear is performed. Firstly, based on the establishment of mathematic model of UAV ground movement and the stress analysis of landing gear when it is under braking control, the behavior and scheme of cushioning mechanism is discussed. Secondly, the software of multidisciplinary design optimization (iSIGHT) combined with the dynamic software(Adams) are applied to the optimization of cushioning mechanism. Then, by taking the requirements of braking condition and shimmy containment as constraint, the size of cushioning mechanism and the spring stiffness are optimized by using the method of point-by-point comparing at macrocosm combined with sequential quadratic programming method. Finally, the taxiing test and stiffness test for the optimal landing gear are carried out. The results show that the compression displacement meets the desired requirement and the efficiency of buffer is increased by 71.5%. The analysis and optimization method provide guidance for the design of UAV articulated landing gear.