Abstract: Taking the excellent watermelon variety ‘Zaojia 8424’ as the test material, different concentrations of EBR were used to soak and spray watermelon seeds under NaCl stress.The effects of different concentrations of 2,4-epibrassinolide（EBR） on watermelon seed germination, seedling growth, and physiological characteristics under NaCl stress were studied, in order to screen suitable EBR concentrations for production practice.The results showed that under the stress of 150 mmol·L^-1 NaCl, the appropriate concentration of EBR significantly alleviated the germination potential and germination rate of watermelon seeds, and 0.05 mg·L^-1 EBR treatment significantly increased the hypocotyl length, main root length and fresh weight of watermelon seedlings after growth.Under salt stress, spraying 0.05 mg·L^-1 EBR on watermelon leaf surface could significantly promote the growth of root length, plant height, leaf length and leaf width of seedlings.The MDA content of watermelon seedlings treated with EBR was significantly lower than that treated with 150 mmol·L^-1 NaCl.The root activity, SOD and POD activities and proline contents of watermelon seedlings treated with 0.05 mg·L^-1 EBR were significantly higher than those treated with other EBR concentrations.In conclusion, 0.05 mg·L^-1 EBR treatment can significantly promote the seed germination and seedling growth of watermelon under salt stress,which can provide reference for salt stress problems in watermelon production.