Excessive air humidity in greenhouses not only directly affects the photosynthesis of plants and the absorption of mineral nutrients, but also contributes to germination and infestation of pathogenic spores. Therefore, in greenhouse production, humidity control is mainly to reduce air humidity. (1) Ventilation. Ventilation should be conducted in a timely manner to promote the exchange of high-temperature air in the shed with external low-temperature air, which can effectively reduce the relative humidity in the shed. Ventilate early in the hot season. Large ventilation, late closing people. Not only should the weather be well ventilated, but on a cloudy day, short-term ventilation should be used when the temperature outside the shelter is high. Generally after each watering, without affecting the temperature conditions, we must increase the ventilation, the moisture out of the shed, and replace the outside world of dry air, reduce the relative humidity of the air inside the shed. (2) Watering. Timely watering in appropriate amount to prevent watering at night, watering in rainy days and watering before the onset of cold wave. Watering should be carried out in the morning on a sunny day so that excess moisture can be discharged and air humidity can be reduced when ventilating at noon. (3) mulching. It can reduce the evaporation of soil moisture and has the effect of significantly reducing air humidity. (4) Intertillage. Uncovered membranes should be more cultivating at appropriate times to cut off the capillary block of large amounts of evaporation of groundwater, while improving the permeability of the soil, which is conducive to the development of the root system. (5) Drip irrigation technology. The use of drip irrigation in combination with deep sorghum mulching film mulching can ensure soil moisture and reduce air humidity (which can be reduced by about 20%). It is an effective way to promote the growth of vegetables and control diseases.