Capsule: The simultaneous effects of light and O3 on the fluorescence properties of grape plants were studied to provide a basis for preventing the interaction effect of O3 and strong light on grape leaf photosynthetic properties. •Light and O3, both individually and together, significantly decreased the Fv/Fm of leaves.•The model is Y (Fv/Fm ratio)=0.73–0.034*A (O3 concentration) −0.022*B (light intensity) −0.018*A*B –5.163*10−3*A2+8.375*10−4 *B2.•This model is constructed as a possible approach to forecast for leaf injury under different O3 concentrations and light intensity combinations.•Using the equation, light intensity that is likely to injure the leaves of Cabernet Sauvignon can be calculated under different O3 concentrations. One-year-old potted Vitis vinifera L. cv. Cabernet Sauvignon grapevines were used to analyze the interaction effects of light and O3 (ozone). Thirteen combinations of different O3 concentrations and light intensities derived from design expert response surface software were conducted, and the result showed that light and O3, both individually and together, significantly decreased the Fv/Fm of leaves, providing a regression equation of Y (Fv/Fm ratio)=0.73−0.034*A (O3 concentration)−0.022*B (light intensity)−0.018*A*B−5.163*10−3*A2+8.375*10−4 *B2. An Fv/Fm value of 0.711 was used as target for model validation, which was used for the obtained 30 O3 concentration and light intensity combinations. Values of 1220μmolm−2s−1 light intensity+100nL/L O3 and 1400μmolm−2s−1 light intensity+117nL/L O3 treatment were selected to validate the model, and the model was validated. This model is constructed as a possible approach to forecast for leaf injury under different O3 concentrations and light intensity combinations. Using this equation, light intensity that is likely to injure the leaves of Cabernet Sauvignon can be calculated under different O3 concentrations. According to the Chinese new national standard, 93.46nL/L O3 is considered the pollution criterion; thus, the leaves of Cabernet Sauvignon were likely injured at light intensity above 1600μmolm−2s−1, suggesting that a protective canopy should be used when light intensity is above this value.