The complex dynamics characters of flywheel governor with feedback control device were studied. The dynamical equation and the state equation of flywheel governor with feedback control device were established according to Lagrangian equations. The chaos forming process of the system was studied by the phase portrait and Poincaré map. A method of controlling chaos by proportional and differential controller was developed to guide chaotic motions towards regular motions. Numerical simulation shows the effectiveness and applicability of this method. The allowable range controlling variable and the steady orbit of the system under controlling were obtained.