A micro electrothermal driver with double layer films has been introduced in this paper. The displacement formula of the bias layer end has been derived, and the rationality of using the nickel as the bias layer has been verified. The finite element simulation of the driver has been carried out by using the CoventorWare. The curve of the bias layer thickness H1 to the driver displacement d, the curve of the driving layer thickness H2 to the driver placement d, and the curve of the driving layer thickness to the stress of the left fixed end of the driver have been obtained at the temperature of 300 K, voltge of 5 V and the response time of 5 ms, thus H2=8 μm has been obtained. The maximum stress of driver is 130 MPa, which is less than the allowable stress of nickel, thus the driver can operate reliably at H2=8 μm. The influence of the machining errors of the driving layer and bias layer thickness on the driver end displacement are analyzed, and it concludes that the machining error of the bias layer thickness(H1) must be strictly controlled during machining. The modal analysis and the antioverload analysis of the driver have been carried out. It has been found that the operating freqiency of the electrothermal driver is 821.011 Hz and has the ability to resist the acceleration of 8 000 g(g=10 m/s2).