Parametric vibrations are widely present in microelectromechanical systems coupled with multi-physical fields. To study the parametric resonance nonlinear dynamics problem existing in electrostatic driven micromirror systems, a class of electrostatic comb-driven micromirrors is used as an example to study the parametric resonance response variation of the system under different factors by fitting the comb capacitance variation with a seventh order polynomial and establishing a micromirror dynamics model. The law of the influence of the change of structural parameters of the micromirror on the torsion angle under static conditions was investigated; the multi-scale method is applied to analyze the action law of system parameters on the change of resonance amplitude in the resonance state and numerically verify the system parameter resonance; finally, the stability of the subharmonic parametric resonance of the system was analyzed and verified using the Runge-Kutta method. It is shown that subharmonic parametric resonance exists in the micromirror system, and factors such as excitation voltage and capacitance fitting parameters can affect the system resonance amplitude; damping can change the system instability region, raise the instability threshold, and affect the occurrence of subharmonic parametric resonance in the system.