Using quinoa variety “Longli 1” as material, we pretreated the seeds and seedlings with different NaCl concentrations (100, 200, 300, 400, 500 mmol/L), determined the seed germination indexes, the contents of chlorophyll, soluble sugar, proline, MDA and the activities of antioxidant enzymes in different period of seedlings to study the effects on seed germination, seedling growth and physiological characteristics of Chenopodium quinoa under salt stress. The results showed: (1) With the concentrations of NaCl increased, seed germination rate, seed energy, seed index and vigor index were increased and then decreased, when the seeds were treated with 200 mmol/L NaCl, the four indexes were increased 6.40%, 28.18%, 20.77% and 30.91% than that of CK; (2) root and stem growth of quinoa seedlings were inhibited when the seedlings were treated with different NaCl concentrations, and the inhibiting effects on stem growth were stronger than that of root; (3) with increasing the NaCl concentrations and prolonging the treatment time, chlorophyll contents of seedling leaves increased and then decreased, soluble sugar, proline and MDA contents increased, and the activities of SOD, POD, CAT and APX also increased. We concluded that the salt threshold value of quinoa was 200-300 mmol/L.