The invention discloses a method and a device for protecting a low-voltage distribution cabinet based on SVG grid-connected test. According to the method, firstly, voltage and current data in a main loop are acquired; then, the power in the main loop is calculated; and finally, the power is compared with a power protection limit value, when the power is larger than the power protection limit value, the SVG device is shutdown. Station-service power in frequent grid-connected test in the station can be protected.