In this study, genetic diversity, trait correlation, principal component and cluster analysis were performed on 630 upland cotton germplasm resources. The results showed that among the 16 traits, the effective boll number and the starting node of the fruit branch had the largest variation coefficient; the genetic diversity of each trait was higher, with an average of 2.11; the correlation analysis showed that the average length of the upper half of the fiber was correlated with the specific strength of the fiber. Fiber uniformity showed a significant positive correlation and the growth period, fruiting branch start node position and fiber elongation also showed a significant positive correlation. The principal component analysis showed that the eigenvalues of the first five principal components of cotton phenotypic traits were all greater than 1, which cumulatively reflected 74.798 of the total information. The eigenvalue of the first principal component was 4.536, the contribution rate was 28.353%, and the eigenvector values of the spinning consistency index, fiber uniformity and fiber upper half mean length were larger. The second principal component was 2.574, the contribution rate was 16.088%, and the eigenvector values of the fiber maturity and micronaire value were larger. The third principal component was 1.941, the contribution rate was 12.133%, and the eigenvector values of the fruit branch number, effective boll number and first fruit branch position were larger. The cluster analysis divided the 630 cotton germplasm materials into 6 categories, of which category II contained 2 materials(Jiarong cotton 7, Sanjiang Dahua), which were the materials owing low lint content and poor fiber quality; the Category III contained 10 materials(Donglanhua, Nandan, Pingyang cotton, Lihu 1, Lidang-Lu 5, Luodiantiezi, Pingtang cotton, Rongjiang cotton, Sandu cotton, Kaimian), which belonged to the materials having the longest average length of the upper half of the fiber and the highest fiber specific strength, which could be used as materials for improving cotton fiber specific strength, output composition and fiber quality.