Abstract：In order to improve the kinematic capability of quadruped robot, from the perspective of bionics, a passive compliant spine of quadruped robot with a variable stiffnet,Four-Leaf Clover spine,is designed by studying the characteristics of vertebral column structure and torso motion of cheetah. Based on that study, in order to study the influence of Four-Leaf Clover spine on the speed, foot force and turn radius of the quadruped robot during the movement, a prototype of bionic quadruped robot with Four-Leaf Clover spine is built, which is DCat Ⅱ, and the experiments on running and turning movement under bound gait are carried out. The experimental results show that the passive compliant spine can reduce the foot force of DCat Ⅱ during the movement. When the overall stiffness of Four-Leaf Clover spine is 681 N/m, the highest steady-state velocity of DCat Ⅱ is achieved, which is 0.92 m/s. The greater the stiffness value of the spine in the direction of yaw is, the greater the turn radius of DCat Ⅱ is.