The goal of this research project is to investigate the relation of central nervous system and body balance function by testing the postural maintenance performance of a knock-out mouse. In the development of the prototype mouse stabilometer system, postural maintenance performance was evaluated and analyzed by measuring the variance of the stress on the pillar with strain gauges. However, with the stage swinging during measurement, the evaluated signal is affected by the inertia of the stage, and requires repeated trials to gain determinate data. Furthermore, without gaining the data on actual body mass movement, the relation of brain function and posture control remains non-committal. Therefore, the technical target is set to compute the center of gravity by applying a mechanical system model of the mouse and device to evaluate the postural maintenance performance. As to improve the prototype device to measure the amplified strain gauge signal with the A-D converter, the design of the pillar was adjusted to maximize the variance within the measurement range of the converter. The influence is simulated and the Center-of-Mass & Strain-gauge distance and Stage-surface & & Strain-gauge distance were modified.