The effects of different temperature (5-45 ℃) and NaCl (0-300 mmol·L-1) on seed germination index and antioxidant enzyme activities of Cynanchum thesioides(Freyn). K. Schum were studied. The results showed that: (1) with the increase of temperature, germination index of seed all increased first and then decreased. The low or high temperature inhibited significantly seed germination. The optimum temperature for germination was 25 ℃, and its recovery germination ratio was over 95% at 5 ℃ and 35 ℃. (2) As NaCl concentration went up, the germination ratio, germination potentiality, vigor index of seed decreased, but relative salt injury rate increased and germination was completely inhibited at 300 mmol·L-1. The root vigor of seed was inhibited significantly only at high NaCl concentration(>150 mmol·L-1), the seed could recover germination after the salt stress was relieved, but it was still inhibited by salt stress. The higher salt concentration, the more prohibitive, and the appropriate content of salttolerant was 65.25 mmol·L-1(the salt content is 0.38%). (3) Under salt stress, the germination ratio was positively correlated with POD and APX, but negatively correlated with O-·2 generation rate and MDA, the vigor index was negatively correlated with CAT. Therefore, the seed germination was significantly inhibited by salt stress, protective enzymes POD and APX played a major antioxidant role during seed germination under salt stress, Cynanchum thesioides(Freyn). K. Schum was suitable for germination in moderate saline soil.