A new design method for non-time based tracking controller of mobile robots is presented. The new design method converts a controller designed by traditional time-based approaches to a non-time based controller using any given action reference. The stability condition of non-time based tracking controller is developed and theoretically proved. The analysis and design methods are exemplified by a mobile robot tracking control problem. The controller has been implemented and tested in a Nomadic XR4000 mobile robot. The experimental results demonstrate the advantages of proposed method.