Abstract: The effects of spermidine pretreatment on relative water content (RWC), contents of chloroplast pigment and soluble protein in leaves of hulless barley seedlings （Hordeum vulgare L. var. nude）under 200mmol/LNaCl stress were studied. Seedlings of control and NaCl treatment were daily sprayed with distilled water + 0.02% (V/V) Tween-80 and irrigated with half-strength Hoagland’s nutrient solution, and Seedlings of Spd pretreatment were daily sprayed with 0.5 mmol/L Spd + 0.02 % (V/V) Tween-80 and irrigated with 0.5 mmol/L Spd + half-strength Hoagland’s nutrient solution for 2 days before NaCl stress. Under 200mmol/L NaCl induced stress, RWC, levels of chloroplast pigment and soluble protein in leaves of hulless barley seedlings obviously decreased, and preliminary supply of Spd could distinctly alleviate their decline. These results suggested that using of exogenous spermidine could obviously alleviate the injury of NaCl stress, and have protective effects on delaying senescence and resisting NaCl stress of hulless barley seedlings.