Abstract: The function between voltage and displacement of actuator and the linear superposing of the actuators for micromachined membrane deformable mirror are analyzed by means of the measured influence function of actuators. The voltage decoupling model for micromachined membrane deformable mirror is established through theoretical and experimental analysis of the fitting aberration of a continuous-surface deformable mirror. The fitting of the former 10-order Zernike mode is carried out. Analyzing the residual fitting error and correction capacity to the former 36-order Zernike mode, the conclusion is that micromachined membrane deformable mirror can be applied to correct the low order aberrations (especially for the former 10-order Zernike mode, with which it has a larger correcting capacity and