Abstract: In order to explore the effect of spermidine（Spd） on Chenopodium quinoa seed germination under salt stress, two Chenopodium quinoa varieties in this study were used as materials and the effect of Spd on physiological indexes such as germination rate, starch content and antioxidant enzyme activity of quinoa seeds under salt stress was analysed. Salicylhydroxamic acid（SHAM）, a specific inhibitor of respiratory electron transport chain, was used to inhibit alternating oxidase（AOX） pathway partially to study correclation of Spd and AOX pathway to seed salt resistance. The results showed that the optimum Spd concentration of different varieties of quinoa seeds was different under NaCl stress. Improvement of α-amylase activity by suitable concentration of Spd promoted starch decomposition and provided ATP for seed germination. Spd eliminated or reduced the production of reactive oxygen species by increasing the activity of antioxidant enzymes such as CAT increasing respiration rate. Exogenous application of appropriate concentration of Spd could improve salt resistance of quinoa seeds, improve respiration rate of quinoa seeds under salt stress, release energy and promote seed germination, and this promoting was related to AOX pathway.