Abstract: Using fuzzy math model and the dyed raw cotton testing,the changes of physical properties of cotton fibers in spinning such as length of fiber,fineness,maturity,neps,breaking strength,and elongation were evaluated by means of the two-grade fuzzy model. A quantitative analysis of these changes in individual process was conducted. The results indicate that with respect to the comprehensive performances of the cotton fiber,the roving exhibits the best,the sliver,the worst,and spun yarn better than the sliver only. These results provide a scientific basis for rational processing and application of cotton.