In this paper, the hyperstability theory applied to the adaptive model-following PID controller is first presented. Second, a new method of frequency domain analysis with the Matlab/Simulink software on the adaptive model-following PID controller is presented, From the simulation results, the step responses of the PID controller with and without the adaptive model-following control effects are discussed. The modelfollowing performances on the frequency domain also show the bandwidth of the PID controller can be improved by a suitable adaptation signal.