Abstract: In order to research the regulating effect of exogenous salicylic acid (SA) on sucrose-metabolizing enzymes activities in cucumber (Cucumis sativus L.), a hydroponics experiment was conducted and combined with different concentrations of SA. The results showed that appropriate SA concentration could promote the growth of cucumber seedling roots, 0.1 mmol/L treatment had the best effect. After SA treatment, the activities of AI, NI and SS (direction of cleavage) were higher than that of the control; the activity of SS (direction of cleavage) reached a very significant difference in 0.1 mmol/L and 0.05 mmol/L SA treatments, but the effect of 0.5 mmol/L SA treatment was not obvious. AI and NI activity were significantly different from that of the control. The activity of SPS decreased after the treatments with different SA concentrations, the difference between the three concentrations treated for 6 days and the control group reached a very significant level, and the effect of 0.5 mmol/L SA treatment was the most obvious, the activity was 1.81 μmol Sucrose/(g·h)FW on the 6th day of the treatment, activity change of SS and SPS had the similar trend. After the treatments with different SA concentrations, the activity of amylase increased with the treatment time extending, then decreased slightly, and was lower than that of the control overall. The effect of 0.05 mmol/L SA treatment was the most obvious, the activity was 2.33 mg/(g·h)FW on the 6th day of the treatment, and it reached a very significant difference level compared with that of the control. In conclusion, appropriate SA concentration treatment could adjust the activities of sucrose-metabolizing enzymes, and promote the growth of Cucumis sativus seedling roots.