The utility model provides a capacitor battery life testing device, wherein the charging and the discharging are integrated as a whole. The device mainly comprises two parts, namely a large-current charger part and a load discharging part, wherein a set of capacitor battery life diagnosis system is built up based on the large-current and multi-rate discharging principle. In this way, the service diagnosis of a capacitor battery can be realized by means of the above single device without the help of any other auxiliary device. The service test of the capacitor battery can be completed automatically without any manual intervention. Meanwhile, the data of the test can be automatically exported.