Abstract: Stepwise regression analysis was used to study the experimental data of yarn spinning,and the results showed that the strength of yarns depends on the quality of cotton fiber,spinning technology and linear density of yarn;the pivotal indexes expressing the cotton fiber quality are cotton fiber length,strength,Micronaire and uniformity.The model of single yarn strength manufacture by combing or carding processes is established according to the findings above,which is a non-linear model having explicit mechanism,few independent variables,and good projecting validity.It is simple and intuitionist,and easy to promote for application.