The article states that due to the low moisture content of fiber produced in ginneries, there is a need for additional humidification, and so far no effective wetting equipment has been developed to meet the demand. It is shown that the reason for the complexity of wetting cotton fiber is that it belongs to the type of non- wetting material, water condensate is in the form of droplets in the fiber and the bonding strength depends on the friction force at the point contact. It has been shown that in the transmission of wetted fiber in the air stream, the droplets on the surface of the fiber can separate under the influence of aerodynamic force and pass into the air, resulting in a decrease in wetting efficiency. The one-dimensional motion of the drop on the fiber surface along the horizontal axis, the conditions of separation from the fiber surface were theoretically analyzed. The laws of motion have been determined. The conditions under which a drop of water remains in the fiber or separates from it and passes into the air stream have been determined. The main factors influencing the separation of a water droplet from a fiber were identified as correlations between air flow rate, water droplet diameter, and mass. It was found that the air velocity, the diameter of the water drop, the amount of separation of water droplets increases with increasing mass, and the amount of separation decreases with decreasing diameter and mass of water droplets. Keywords. Water droplet, fiber wetting, wetting technology and equipment, water condensate, face resistance force, drop midel cutting surface, face resistance, lifting force coefficient.