Abstract: In order to investigate the effects of drought stress on plant physiological characteristics and seed germination of different varieties of Linum usitatissimum,three flax varieties, Longya 12,Lunxuan 2 and Jinya 11,were selected as experimental materials cultured with nutrient liquid sand under greenhouse conditions.The plant height, branch number of main stem and physiological and biochemical indexes of leaves of the 3 L. usitatissimum varieties were analyzed under PEG-6000 stress including four water potential gradients（0,-0.4,-0.8 and-1.2 MPa） after 60 days of growth. The results showed that the plant height, branch number of main stem, relative water content of leaves and stomatal conductance of L. usitatissimum decreased with the increase of water stress degree.Drought stress could significantly affect the physiological characteristics of L. usitatissimum on the whole, and the soluble protein content, malondialdehyde（MDA） content and catalase activity of L. usitatissimum increased continuously with the intensification of drought stress. The soluble protein content in leaves of Longya 12 and Lunxuan 2 was significantly lower than that of Jinya 11（p＜0.05）, while the MDA content of Longya 12 was significantly lower than that of Lunxuan 2 and Jinya 11（p＜0.05,except for severe drought stress）.Also, the seed germination rate of Longya 12 was significantly higher than that of Lunxuan 2 after drought resistance treatment.According to the comprehensive comparative analysis, Longya 12 had better drought resistance than Jinya 11 and Lunxuan 2, and was more suitable for popularization and utilization in the arid areas of north China.