The invention discloses a rotary dehumidifier-type condensation dehumidification device for metal-clad equipment and a control method of the rotary dehumidifier-type condensation dehumidification device. The device comprises a rotary dehumidifier, ventilation units and an automatic condensation dehumidification controller, wherein each ventilation unit is arranged on the metal-clad equipment and is communicated with the rotary dehumidifier through an air inlet pipe and an air return pipe. The device is simple in structure and high in automatic degree; automatic long-distance control on condensation of the metal-clad equipment is achieved; the starting time of the dehumidification device is greatly shortened; the fire risk caused by overheating of the dehumidification device in each metal-clad equipment is avoided; the internal humidity control of single metal-clad equipment is relatively uniform; the humidity target value can be freely set; the phenomenon of non-uniform dehumidification in large metal-clad equipment is avoided; the dehumidification effect is good; the temperature rise in the metal-clad equipment is not caused in the dehumidification process; and the risk that an insulating material ages too fast is avoided.