Abstract: In this study, a total of 141 recombinant inbred lines（RILs） of Linum usitatissimum（flax） were used as experimental materials to identify the drought resistance at seedling stage and screen the drought resistance indexes.Nine traits, including plant height, root length, leaf fresh weight, stem fresh weight, root fresh weight, root dry weight, leaf dry weight, stem dry weight and root-shoot ratio, were determined under water stress.Drought resistance-related indexes were screened by principal component analysis（PCA） and correlation analysis（CA）.The D value of drought resistance was used to comprehensively evaluate the drought resistance of 141 inbred lines.The results showed that there were abundant variation among different materials under drought stress, and the average variation coefficient of 9 phenotypic traits was 40.70%,the maximum variation coefficient of root dry weight, and the minimum variation coefficient of plant height and root length.PCA and CA showed that the root-shoot ratio and root traits had significant effects on drought resistance, which could be used as comprehensive indexes for drought-resistant identification at seedling stage.The comprehensive drought-resistance D-value clustering classified the tested inbred lines into four groups: strong drought-resistance, weak drought-resistance and non-drought-resistance, among which the drought-resistance of No.11 and No.14 was the strongest.These RILs were divided into four groups based on D-value clustering of comprehensive drought resistance, namely strong drought resistance, drought resistance, weak drought resistance and no drought resistance.Among them, the RIL No.11 and RIL No.14 showed the strongest drought resistance.