The industrial dehumidifier makes use of the principle of moisture condensation in the air. Through the function of the fan, the air in the cabinet is constantly flowing through the cold end of the dehumidifier. So the moisture of the air in the cabinet is continuously precipitated, and the absolute humidity of the air inside the cabinet is reduced. The dehumidifier can also heat the air after dehumidification, improve the air saturation, and reduce the relative humidity in the cabinet. Dehumidifier ensure the ideal temperature and humidity inside the control cabinet and protect the electrical components in the cabinet to operate within a controllable range.