The inertia sensitive component of a force-balanced vacuum microelectronic accelerometer is effected by both the elastic force and the electrostatic force,and its total stiffness is the sum of the mechanical stiffness of the beams and the equivalent stiffness produced by the electrostatic force. In considerasion of the effect of emitting tip array,this paper introduces a revised constant α greater than 1 to compute the actual electrostatic force by using the model of a parallel plate capacitor. The analysis shows that the linearity and sensitivity of the vacuum microelectronic accelerometer has been improved by increasing preload deflection voltages,so the stiffness and damping ratio of the system can be adjusted by modulating the voltage between the two deflection electrodes. Considering the affect by a pull-in,the displacement of proof mass must be less than one-third of the original distance between two deflection electrodes. Moreover,in order to obtain good dynamic characteristics,an optimum working point determined by the preload deflection voltage must be set. The experimental results show that the nonlinearity and sensitivity of the accelerometer are 0.95% and 557 mV/g when the deflection voltage and the emission voltage are 5.478 V and 1.953 V,respectively,which indicates that the sensor has good performance.