In order to determine the effect of hydrogen peroxide on the physiological index of wheat seedlings under salt stress,wheat (Triticum aestivum L.cv.‘Zhengmai-004’)seedlings were treated with hydrogen peroxide,hydrogen peroxide treatment in combination with catalase (CAT) and ascorbate acid (AsA).The results showed that treatments with exogenous H₂O₂ significantly decreased MDA content,O-·₂ production rate,increased the activities of SOD,POD,CAT,APX and GSH content in wheat seedlings under salt stress,and remarkably promoted wheat seedling growth (plant height,dry weight,root length and root dry weight).The promoting effect of exogenous H₂O₂ on salt stress could be reversed by the addition of CAT and AsA.It was suggested that exogenous H₂O₂ induced changes in MDA,O-·₂,antioxidant enzymes and antioxidant compounds were responsible for the increase in salt stress tolerance observed in the experiments.Therefore,H₂O₂ may participate in antioxidant enzymes and antioxidant compounds induced tolerance of wheat seedlings to salt stress.The results also showed that exogenous H₂O₂ had a positive physiological effect on the growth and development of salt-stressed seedlings.