To monitor autocorrelation process accurately, state space model is introduced into statistical process monitoring,
and then state variable is chose as statistics of statistical process control(SPC). Based on the analysis of common minimum
mean square error(MMSE) and PID controllers, this paper proposes a general design method and basic principle of feedback
controller of engineering process control. According to this method, two novel feedback controllers are designed, which
demonstrate better monitoring performance comparing with controllers of MMSE and PID when step disturbance occurs in
process mean.