In order to reduce reactive power loss in power systems, parallel capacitor banks are usually used to improve power factor. In practical applications, the accident rate of the capacitor compensation device is relatively high, which is determined by the characteristics of the working state of the capacitor device. Therefore, it is very important to check the capacitor device regularly, find the defects of the capacitor early, and avoid the expansion of the failure. The automatic capacitance and inductance tester can measure a group of single capacitors connected in parallel without disconnecting the wires, and can also measure the inductance. The wiring is convenient and the operation is simple, which greatly improves the efficiency of on-site testing. It can also avoid the possibility of error caused by disassembly and assembly of the lead.