Republic of Uzbekistan produces more than 3000000 tons of cotton per year, 800000 tons of this harvest is a high quality fiber which is exported to abroad. One of good reason, and global task of production high quality fibre, it is value and request from other countries. A main point of taking high quality fiber depends on previous cultivation. Previous cultivation consists of following technical processes: 1. Cotton transportation from bale with help of air through the pipes. In this process, there is considered three - dimensional transition of various particles of cotton in air streams. In the scientific article, it is theoretically investigated the movement of particles of a cotton in air streams. 2. On factories the cotton is transported through pipelines by means of an air stream. Cotton getting to a stone catcher is exposed to percussive loading. In this technological process, problems of preservation of natural quality of cotton and seeds are considered. 3. Squashing air from cotton in separator. In this process, a modification air pressure depends on denseness of a stream of cotton. The movement of cotton and air is considered in the form of two component medium. 4. Cotton getting to the chamber of the gin, through teeth of a saw and kolosnic, received considerable loads. Such loads often damage and break natural qualities of fiber. Here, research is conducted about interaction of cotton with saw cylinder, including dry and viscous friction cotton with saw.