The fundamental structure and channel assignments for actuator mirror of deformable mirrors based on microelectromechanical system(MEMS) technique are introduced.The deformation principle of MEMS deformable mirrors(MEMS-DMs) is analyzed.The relation between the deformation of the mirror surface and the voltages applied to the mirror electrodes is deduced.The composition and testing principle of the computer-controlled stroboscopic microscopic interferometer system are analyzed.The static voltage versus displacement curve,surface shape map and out-of-plane-deflections and resonant frequency of MEMS-DMs are measured.The experiment shows that the test results agree well with the theory analysis.