Hopf bifurcation theory was briefly presented. The state feedback Hopf bifurcation controllers with variable gains were designed for a Van der pol oscillator and a 2-D nonlinear system giving rise to sub-critical Hopf bifurcations. Lyapunov stability theorem is used to prove the validity of the controllers. The maximal characteristic of this state feedback Hopf bifurcation controller is that it is irrelevant to the parameter of the system and the controller can eliminate Hopf bifurcation and guarantee asym...