Abstract: This papers considers the design of the mechanism & control system of a nonholonomic wheeled mobile robot. Selecting newly designed MCU chip of Cygnal C8051F005 as the CPU of control system and Maxon DC servo motor of Switzerland as driver, we designed a nonholonomic wheeled mobile robot basing on nonholonomic restraining condition and nonholonomic motion planning theory. It can track any kind of straight track and arc track, rotate with zero radius, and also can move along any curved path. At last, an experiment on following a straight path and an arc path has been performed.