The omnidirectional walking robot with a steering-wheel synthesizes the mechanism features of legged robot and vehicle’s steering wheel. To investigate the kinematic characteristics and motion control systematically, the design idea, mechanism features and kinematics principle of the robot are introduced. Then an equivalent manipulator model is built, the Jacobian of the manipulator is given and dynamics both in joint space and Cartesian space are developed, the resulting nonlinear closed-loop control system can be obtained based on the formulated dynamics equations. The co-simulation PID control of omnidirectional motion is implemented based on ADAMS and Matlab/Simulink, the experiments on the prototype is performed. The simulation and experiments validate that the robot with a steering wheel can be manipulated flexibly and accurately in omnidirectional motion, and the control method is simple and reliable.