To address the insufficient adaptability of the current guidelines in the Northwest Plateau region, this study investigates the genetic diversity analysis of flax germplasm resources based on DUS test traits and the screening of local standard flax varieties. The results show that the coefficient of variation of 14 quantitative traits of 285 flax germplasms varies from 4.91% 29.55%, and the Shannon-Weaver index ranges from 1.021 to 2.073. The Shannon-Weaver index of quality traits and pseudo-quality traits ranges from 0.225 to 0.991, indicating the rich genetic diversity of the selected flax varieties. Through analysis, cluster analysis, and principal component analysis, the 285 flax varieties can be divided into 6 categories at a Euclidean distance of 20.13 The principal component analysis shows that the cumulative contribution rate of the 7 extracted principal components reaches 74.502%, and finally 20 representative flax are screened out. This study provides new insights into the identification methods of flax germplasm resources and guides the regional selection of standard varieties in flax DUS tests. At same time, it provides a reference for the revision of China's flax DUS test guidelines by comparing the UPOV's flax DUS test guidelines.