The micro-actuator with the torsion beam and the cantilever beam on silicon is designed and analyzed, which is actuated by electrostatic force. Based on the torsion dynamics theory, the technique and relative formula are presented for analyzing the actuating voltage and the switching time, on which the effect of the air squeeze film damping is already considered. The optimized results of the structural parameters are compared between this technique and the finite element modeling (FEM). The optimized result of parameters is as: length, width and thickness of the torsion beam are 700, 12, and 10μm, length and width of the cantilever beam are 1900 and 1000μm, length and width of the balance beam are 100 and 1000μm, and distance of the upper and lower electrodes is 55 μm, respectively. The actuating voltage is about 50 V, and the switching time T off and T on are about 5 and 12 ms, respectively. The computed results show that the air squeeze film damping is an important factor for the study of dynamic response on micro-actuator. Finally, an optical technique is described for the measurement of the actuating voltage and switching time of the device, and the difference between the experimental results and theoretical datum is discussed.