The purpose of this paper is not to elaborate the bionic pattern of walking robot, but to elaborate our own simple idea of a 4 degree of freedom (DOF) walking robot with the ability to walk on flat surfaces, rotate and climbing upstairs, which is composed of vertical moved legs with a rotary foot and a controlled mass for stabilizing. In this paper, based on the former idea, a prototype model of a 3-DOF walking robot is presented for walking only on flat surfaces. This walking robot is actuated by servo motors. The paper covers the kinematics, centre of gravity analysis, description of the robot and its control system made using Pololu controller. Experiments confirmed the feasibility of the proposed design.