The Washout filter controller and the nonlinear state feedback controller are respectively adopted to control Hopf bifurcation in the equal effective non-linear mathematical model of brushless DC motor system, by introducing the calculation method of limit cycle curvature coefficient, the limit cycle curvature coefficient of system is obtained and expressed as a function of control parameter, the periodic solution’s amplitude and the Hopf bifurcation type of system are discussed by the control parameter, it is concluded that if the curvature coefficient is less than zero, the unstable limit cycle of original system is controlled to a stable limit cycle. Then two control methods are compared, results shows that washout filter has certain advantages compared to nonlinear feedback controller. Finally, all the results obtained are verified by numerical simulation.