Abstract: To explore the relationship between Micronaire value and spinning quality of cotton fiber, the paper analyzed series indexes obtained though single bale spinning with different Micronaire values which could affect the yarn quality. The conclusion is that the correlation between Micronaire value and the strength of yarn, hairiness index with a protruding length of 2 mm and end breakage is non-linear; the correlation between Micronaire value and yarn evenness is significant positive; and the correlation between Micronaire value and number of nep is significant negative. So Micronaire value must be allocated rationally according to the use of yarn to ensure the quality of yarn during the course of spinning.