Taken the varieties of Radix Isatidis from Bozhou in Anhui Province as experimental material, under 100 mmol/L NaCl salt stress, the effects of exogenous GA₃ were studied on seeds germination and seedling physiological biochemical indexes. The results showed that when the concentration of exogenous GA₃ 100 mg/L, seeds germination and seedlings growth were optimal; at the same time, photosynthetic rate, transpiration rate, stomatal conductance and intercellular CO₂ concentration reached the maximum values, were CO₂ 5.53 μmol/(m²·s), 0.56 mmol/(m²·s), H₂O/216 mmol/(m²·s) and 287 mg/L, respectively; MDA content in seedling leaves was the lowest while the activities of POD and SOD were the highest, were 0.336 μmol/g FW, 26.65 U/(g·min) FW and 272.53 U/(g·min) FW, respectively, which can effectively alleviate salt stress damage to seeds germination and seedling growth of Radix Isatidis.