Elevated ozone levels can harm winter wheat plants, affecting their ability to photosynthesize. Two wheat varieties, Yangmai 16 and Yannong 19, were studied using a special ozone-free air system. After 35 days of ozone exposure, both varieties showed a decrease in photosynthetic rate. Yannong 19 was more affected than Yangmai 16. The chlorophyll levels changed, and the efficiency of photosynthesis decreased. Yannong 19 had a more significant reduction in photosynthetic efficiency compared to Yangmai 16. The study also found differences in the defense and repair systems of the two wheat varieties when exposed to elevated ozone levels.