The invention discloses a dehumidification device for a hermetically sealed control cabinet interior. The dehumidification device for the hermetically sealed control cabinet interior comprises a cabinet body bottom plate, a ventilation hole is formed in the middle of the cabinet body bottom plate, and a guide rail, a heater, and a long-stroke electric cylinder are arranged on the upper surface ofthe cabinet body bottom plate; the guide rail is provided with a sliding block matched with the guide rail for use, the top of the sliding block is connected with a supporting plate, and a push rod ofthe long-stroke electric cylinder is connected to the side surface of the sliding block through a push rod connecting member; the supporting plate and the sliding block are driven by the long-strokeelectric cylinder tohorizontally movealong the guide rail, a short-stroke electric cylinder is arranged on the upper part of the supporting plate, and an axial fan is arranged on the lower part of thesupporting plate; and a push rod of the short-stroke electric cylinder penetrates through the supporting plate and then is connected with a sealing gasket positioned on the lower part of the supporting plate, and a ventilation assembly is arranged on the upper part of the axial fan. According to the dehumidification device for the hermetically sealed control cabinet interior, a combined method ofheating and exhausting is used fordehumidifying gas inside a cabinet cavity, and the ventilation hole of a control cabinet can be sealed after dehumidification.