Leymus chinensis (Trin.) Tzvel. (Poaceae) is a perennial, high quality grass and is the dominant species in Songnen plain, China. Seed germination and seedling growth of Leymus chinensis were investigated under eight levels of salinity stress (0, 50, 100, 150, 200, 300, 400, 500 mmol/L NaCl) and three temperature regimes (16/28℃, 5/28℃, and 5/35℃) and then after the salinity stress was removed. The results of a two-way ANOVA showed that salinity (including when the salinity stress was removed), temperature and their interaction significantly affected the seed germination and seedling growth of L. chinensis. The highest germination percentage was obtained under non-saline conditions, and with an increase of NaCl concentration, germination significantly decreased. Seed germination at the moderate temperature regime of 5/28℃ was optimal, with 25.3% of seeds germinating in 200 mmol/L NaCl. The salinity inhibition for seed germination was greatest at 5/35℃ when no seeds germinated above a concentration of 100 mmol/L NaCl while the salinity inhibition was lightest at 5/28℃. After 18 days, seeds were transferred from salt solutions to distilled water and those from high salinities (≥150 mmol/L), the seed germination recovered most quickly at 5/28℃, and slowest at 5/35℃. At 16/28℃, germination percentage increased with the pre-treatment NaCl concentration. At 5/28℃, germination increased between 0 to 150 mmol/L and then changed little when NaCl was more than 150 mmol/L. However, seed germination percentage increased from 0 to 100 mmol/L and then decreased from 100 to 500 mmol/L. Seedling growth was also significantly inhibited by salinities. Under NaCl stress, seedlings grew best at 16/28℃, moderately well at 5/28℃ and seedling growth was significantly inhibited at 5/35℃. Seedlings which germinated after being transferred to distilled water showed different growth patterns with different pre-treatment salinity and temperature regimes. At 16/28℃ and 5/28℃, root and shoot length increased with a pre-treatment NaCl concentration of 0-100 mmol/L but changed little when it was more than 100 mmol/L. At 5/35℃, the maximum values of shoot and root length occurred at 100 mmol/L NaCl, and then decreased when the concentration was over 100 mmol/L.