Objective To develop a computer-auto-controlling and analysis system for Tail suspension. Methods Combining the advantage of computer science, engineering and animal behavior into tail suspension test. The "energy" index was developed. The system was validated with antidepressants such as imipramine and paroxetine. Results The measuring principle is based on the energy developed by mice trying to escape from their suspension. During the test, the movements of the mice are analyzed in terms of force, energy and power developed over time. Each mouse issuspended by the tail using adhesive tape to a hook connected to a tail test sensor. The tail test sensor fixed to suspension bar picks up all movements of the mouse and transmits these to a signal regulation unit and transmission circuit, which amplify, filter and digitalizes the signals. The signals are displayed visually in waveform. Activity time, immobility time, energy are continuously updated. The correlation coefficient of "immobility time" collected by computer and manpower was 0.94. Using this system, both imipramine and paroxetine could decreased the immobility time and paroxetine could increased the energy induced by mice(both P < 0.01). Conclusion A stable computer-auto-controlling and analysis system for Tail suspension was established and could be used to screen the antidepressants.