Abstract:429 superior cotton accessions from cotton regions, both in China and abroad, have been identified in 2 places for 2 years. We have made a comprehensive evaluation of 15 phenotypic traits through the field observation and fiber quality testing. The results showed that the variation coefficient of height of first sympodial branch, boll number and sympodial branch node was the biggest of all traits. The average of genetic diversity index of all traits was high for 2.02. The principal components analysis calculated three common factors in every class. The results demonstrated that upland cotton breeding should focus on the varieties, which had a good fiber quality (the higher fiber length and strength) and a higher lint percentage and more bolls. Cluster analysis showed that all materials could be classified into 10 groups, including the first big groups accounted for 76.9% of the total. Each group had different characteristics and showed abundant genetic diversity. There was no obvious evidence that the groups had corresponding relationship with the origins of accessions.