The invention relates to a moisture-proof dehumidification device for a high-voltage chamber of a substation. The moisture-proof dehumidification device comprises the high-voltage chamber, a high-voltage switch cabinet and a cable channel, wherein the high-voltage switch cabinet is arranged in the high-voltage chamber; the cable channel is arranged under the ground of the high-voltage chamber; a blind window is arranged at the upper part of a wall of the high-voltage chamber; a fan is arranged on the ground of the high-voltage chamber; an air inlet of the fan is connected with an exhaust pipe; the other end of the exhaust pipe is communicated with the lower surface of the high-voltage switch cabinet; an air outlet of the fan is connected with two air outlet pipes; one air outlet pipe is communicated with the inside of the high-voltage chamber; the other air outlet pipe is communicated with the outside of the high-voltage chamber; and valves are arranged on the two air outlet pipes. The moisture-proof dehumidification device compels a gas in the high-voltage chamber to adversely circulate, directly exhausts moist air from the lower part of the switch cabinet to the outdoor atmosphere to accelerate air circulation in the cabinet and simultaneously can heat the lower part of a cabinet body by the temperature, so that the target of reducing condensation can be achieved.