Abstract: By a way root injection and foliar spray with 50 mg·L-1 of salicylic acid (SA), the physiological responses of Cucumis sativus L. (cv. Xinjinyan No.4 ) on exogenous SA were studied under NaCl stress. The results showed that exogenous SA enhanced the accumulation of soluble sugar and proline (Fig.1), improved the activities of superoxide dismutase, peroxidase and catalase (Fig.2), and decreased the malondialdehyde content and electrolyte leakage (Fig.3) in leaves, increased the water content of dry weight in whole plant under NaCl stress, thus effectively alleviated the inhibition of NaCl to seedling growth. These results suggested which exogenous SA has a important role on NaCl tolerance of cucumber seedlings via the osmotic regulation and antioxidation, water balance and membrane stability.