Abstract: For investigating salt tolerance of cotton and its effect factors in Xinjiang Uygur Autonomous Region, the experiment were carried on salt tolerance of cotton under the condition of different mineralization of irrigation water and the soil salinity. Results indicated that the relationship between soil salinity or mineralization of irrigation water and the cotton relative emergence rate was linear. The mineralization of irrigation water was changed with the soil saline and alkaline degree. The mineralization of irrigation water was less 5 g/L when the soil salinity was hereinafter 0.33%, the mineralization of irrigation water was less than 3 g/L when the soil salinity was between 0.33% and 0.5%, and the irrigation water was fresh water when soil salinity exceeded 0.5%. Contrasting the two factors affected on emergence rate of the cotton, the results indicated in the medium grade and hereinafter saline-alkaline soil, the effect was bigger in the mineralization of irrigation water than soil salinity. Combining investigation of cotton emergence rate in field, the results indicated that the critical mineralization of irrigation water was 4.28 g/L, and the cotton salt tolerance was 0.58% in soil. The study provides reference for further research of salt tolerance of cotton, and possesses great significance in directing local cotton production.