Aiming at the problem that the legged robotic is subjected to a large reverse impact force from the ground during extreme movement such as running and jumping,the skeletal muscle system of the legs of felines was taken as the bionic object by using bionics method,and the closed-chain linkage mechanism was optimized by introducing variable stiffness elastic rod.A legged robotic leg mechanism with simple structure was designed,which could effectively store ground reverse impact force and converted it into kinetic energy during movement.The mathematical model was established,the elastic element with variable stiffness was quantitatively analyzed,and the kinematic analysis of the linkage mechanism was carried out by using vector loop method.The virtual prototype of the two single-leg mechanisms before and after optimization was established,the control system was designed with MATLAB software,and ADAMS was used to simulate the virtual prototype of walking and jumping,and the comparison test of the two kinds of leg mechanisms before and after optimization was conducted.〖BP(〗On this basis,a physical prototype was built to further verify the feasibility of the mechanism and the ability of the elastic rod adopted by the mechanism to convert the ground reverse impact force into kinetic energy when moving.〖BP)〗On this basis,the prototype was built and verified by experiment.The experimental results show that the proposed legged robot leg structure is feasible,which can convert the impact force from the ground into kinetic energy and improve the jumping height of the legged robot.