Abstract:In this study, oat cultivars ‘Yanke 2’ (high grain cadmium accumulation, Yh) and ‘20091971’ (low grain cadmium accumulation, Yl) were used as materials, and pot experiments were carried out under the condition of soil Cd stress. The changes of plant growth, leaf photosynthetic physiology and antioxidant enzyme activities of the two types of oats were measured, and the differences in the responses of the two cultivars to Cd stress were discussed. The results showed that: (1) under Cd stress, the plant growth, gas exchange parameters and chlorophyll fluorescence parameters of high Cd accumulating oat cultivar (Yh) and low Cd accumulating oat cultivar (Yl) were inhibited, and the dry weight per plant, Pn and qP were the most prominent. The decrease rates of Yh and Yl were 38.2% and 40.8%, 35.0% and 57.1%, 14.7% and 27.3%, respectively. (2) Cd stress induced the activities of antioxidant enzymes in leaves of the two types of oat cultivars, especially SOD activity was significantly enhanced, Yh and Yl increased by 41.9% and 44.9%, respectively; at the same time, Cd stress significantly increased MDA content, Yh and Yl increased by 22.2% and 18.1%, respectively. The study found that under Cd stress conditions, compared with the low Cd accumulation varieties, the high Cd accumulation varieties had higher biomass and antioxidant enzyme activities, as well as stronger net photosynthetic rate and excellent chlorophyll fluorescence characteristics, showing a relatively high level of chlorophyll fluorescence and strong Cd resistance.