Traditional grinding robots are fixed on the base or installed on the guide rail, which has low mobility and limited working area. Aiming at the high mobility of indoor wall grinding robot, a four-wheel grinding robot mobile platform based on Mcnamu wheel is proposed. Firstly, the structure of a single Mcnamu wheel is analyzed to understand its motion mode. Then, the forward and inverse kinematics of the Mcnamu four-wheel mobile platform is analyzed, and the inverse kinematics formula of the four-wheel mobile platform is obtained. In addition, the inverse kinematics model is established in Simulink. Finally, the forward kinematics is verified in Vrep. The results show that the analysis of the Mcnamu wheel mobile platform is correct, and the Mcnamu wheel mobile platform can fully improve the mobility of the grinding robot and lay a good foundation for the automatic grinding of the robot.