The invention discloses a wet type sauna steam supply system. The wet type sauna steam supply system comprises a steam generating device, a steam supply pipeline, a heating device, humidity monitoring devices, temperature monitoring devices, automatic ventilation windows and a main control device; the steam generating device comprises a cover plate, a shell, a liquid accumulation tank and an atomizer, wherein the liquid accumulation tank is internally filled with liquid water, and the atomizer is capable of atomizing the liquid water into water vapor; the steam supply pipeline is connected to a steam outlet hole of the steam generating device and a plurality of sauna rooms and is capable of conveying the water vapor to the multiple sauna rooms; the heating device heats steam generated by the atomizer; the humidity monitoring devices and the temperature monitoring devices are arranged on roofs of the multiple sauna rooms separately; the automatic ventilation windows are arranged on wall plates of the multiple sauna rooms; and the main control device controls opening and closing of the steam outlet hole according to the humidity information and controls opening and closing of the automatic ventilation windows according to the temperature information. The steam supply system has the advantages of being simple in structure, convenient to operate and reliable in use; and the temperature and the humidity in the sauna rooms can be monitored in real time, and start and shutdown of all functions of the sauna rooms can be automatically controlled.