Due to its unique body structure and movement mode, the legged robot has strong terrain adaptability and can move in many complex environments. However, the robot's feet will frequently contact with the ground during the movement, and will be subject to greater ground impact. The flexible foot structure can effectively reduce the ground impact. The leg and foot structures, and locomotor characteristics of cats and insects were analyzed based on bionic principles. Combined with the structural characteristics of the small-legged robot, the structure and function of the flexible foot end is analyzed.