Based on the electrostatic force computation formulas of rectangle capacitor with edge effects

a dynamic characteristic model of a torsion micromirror is illustrated.The load is calculated by Romberg numerical integration procedure and an iterative refinement homogeneous capacity high precision integration method（IRHCHPIM）is put forward to solve the nonlinear different equation.Numerical calculated results show that parameters

such as voltage

geometry dimensions of the micromirror and electrodes etc

can affect the edge effect

which leads a larger error in dynamic analogy.Therefore the edge effects should be considered at analyzing the mechanical characteristics of micromirror.