The utility model provides a control circuit of a low-voltage reactive compensation device. The control circuit of the low-voltage reactive compensation device comprises a control module, a power supply module, an HCI (Human-Computer Interaction) module, a collection module, a data storage module, a communication module, a switching control circuit, a zero passage switching module and a protection alarm module. The control module is respectively connected with the power supply module, the HCI module, the collection module, the data storage module, the communication module, the switching control circuit and the protection alarm module. The switching control circuit is sequentially connected with the zero passage switching module and a capacitor. According to the technical scheme of the utility model, a reactive compensation device can be compensated reactively by the above control circuit according to an improved nine-zone diagram. Due to the adoption of the control circuit, the problem that the switching operation must to be performed frequently during the control process of the traditional nine-zone diagram is overcome. Meanwhile, the control circuit has the advantages of low cost and flexible application. When the control circuit is in use, the fast and accurate switching of the capacitor can be realized.