Crops are often affected by NaCl, giant ragweed (Ambrosia trifida L.) and freeze-thaw stress simultaneously during their growth, and many areas in Northeast China are facing such serious ecological stress problems. In this experiment, the physiological responses of rye seedlings to NaCl and A. trifida extract stressor (AES) in a freeze-thaw environment were studied by artificial simulation technique. Malondialdehyde net photosynthetic rate (Pn) and transpiration rate (Tr) were determined and analyzed. The results showed that: After stress treatment, MDA and SP contents of rye seedlings increased by 19.48%-88.96% and 22.54%107.30%, SOD and CAT activities increased by 4.42%-26.60% and 23.31%-64.68% and Pn and Tr decreased by 40.00%-71.67% and 20.00%-80.00%. In the face of stress, rye seedlings can reduce the damage caused by stress by increasing osmotic substance and antioxidant enzyme activity, so as to adapt to the environment. The results revealed that combined NaCl, AES and freeze-thaw stress had a significant superposing effect on plants compared with single NaCl, AES and freeze-thaw stress. Net photosynthetic rate (Pn) and transpiration rate (Tr)as photosynthetic indices, are easily affected by the environment, and the photosynthetic physiological characteristics of plants will decrease significantly under external stress.