In order to solve the problem that sealing liquid is difficult to replenish in the prior art, the utility model provides a sealing liquid replenishing device which comprises a sealing tank connected with a supply pipeline and a reactor electrically connected with a motor, a mechanical seal is further arranged between the reactor and the motor, and the sealing tank is connected with a mechanical seal pipeline. And a pressure regulating valve is also arranged between the sealing tank and the supply pipeline. The sealing liquid can be automatically supplemented, long-term special protection of personnel is not needed, manpower resources can be saved, and device faults can be avoided.