Abstract: Medicago sativa and Leymus Chinesis were exposed to different content of NaCl (26 mmol/L(T0), 125mmol/L(T1), 216mmol/L(T2), 308 mmol/L(T3)) in a controlled pot culture system for 30 days Growth reduction by salt stressed was significantly greater in Medicago sativa than in Leymus Chinesis and Leymus Chinesis represented a higher salt resistance than Medicago sativa. The salinity critical values of NaCl concentration in soil were 130mmol/L for Medicago sativa , and 254 mmol/L for Leymus Chinesis. In total salt content the values were 0.35% and 0.59%, respectively The effect of salt stress on net photosynthesis rate (NPn) was more distinct in Medicago sativa than in Leymus Chinesis Salt stress decreased the content of K, but did not affect the contents of N and P Comparison with Leymus Chinesis, Medicago sativa showed a lower specific absorption rate (SAR) of K, but a higher SAR of Na.