Abstract: A novel mobile mechanism is proposed.Its robotic feature is that it has two feet and is able to perform a gait similar to walk with its feet touching the ground.Its mechanism characteristics include:it is an open chain serial mechanism with three links;it consists of three mechanical units and two revolute joints;it has two degrees of freedom;and it is an underactuated mechanism driven by only one actuator.Gait analysis is carried out and computer simulation is performed to verify its feasibility.Then stability analysis is carried out and the concept of this mobile mechanism is extended.Two prototypes are manufactured and the desired motion is realized.