The utility model relates to a grounding line connection device for a low-voltage circuit breaker, and the device comprises a plug-in type wire clamp, an L-shaped connecting frame, an insulating handle, and a bolt. One end of the plug-in type wire clamp is provided with a U-shaped groove, and the other end of the plug-in type wire clamp is riveted to a long arm of the L-shaped connecting frame. A short arm of the L-shaped connecting frame is connected with the insulating handle through the bolt. A grounding line can be connected to the device through a bolt. The outer layer of the plug-in type wire clamp and the outer layer of the L-shaped connecting frame are coated with an insulating material layer. The device can protect the insulating layer of the grounding line from being damaged during suspension, saves time and labor, improves the work efficiency, is reliable in suspension, is good in grounding effect, prevents a user from reversely feeding electricity, and guarantees the safety of a worker.