Abstract: The aim was to lay the preliminary foundation for screen and breed somatic salt tolerant mutants of flax. Seedlings were stressed with NaCl (0, 100, 150, 250 mmol/L), biochemical characteristics (composition and content of chlorophylls, proline, soluble sugar, soluble protein, betain contents) of the seedling were detected; their salt tolerances were determined by data analysis and comparison. From biochemical characteristics of the seedlings, after treated with 250 mmol/L NaCl, proline contents of HIZ019 and ‘Tianxin3’ were significantly higher than that of others. Soluble sugar contents of YOI303 and YOI254 were significantly higher than that of others. Soluble protein content of YOI254 was significantly higher than that of others. Betain contents of HIZ019 and ‘Tianxin3’ were significantly higher than that of others. In a word, flax seedlings of YOI254, ‘Tianxin3’, HIZ019 species were more salt tolerant than that of others.