【Objective】 To investigate the effects of different light exposure durations and intensities on the sugar, acid, and flavonoid contents of Cerasus humilis fruits, and to provide a reference basis for further exploration of the molecular mechanisms underlying the influence of light exposure on fruit quality. 【Methods】 The C. humilis varieties ''Nongda 6'' and ''Nongda 7'' were used as experimental materials. Fruit bags with three different light transmission rates (30%, 55%, and 100%) were respectively applied during the fruit enlargement period and color conversion period to measure the fruit weight, titratable acid content, soluble solids content, and flavonoid content. 【Results】(1) The single fruit weight and soluble solids content of both varieties were lower during the fruit enlargement period than during the color conversion period, and both decreased gradually with increasing light-blocking rate of the fruit bags. (2) The titratable acid content of ''Nongda 6'' was significantly reduced under bagging treatment, and the higher the light blocking rate of the fruit bag and the longer the bagging time, the more pronounced the reduction in acidity. In contrast, the titratable acid content of ''Nongda 7'' was less affected. (3) The flavonoid content of bagged ''Nongda 6'' was higher than the control, increasing first and then decreasing with the increase in light-blocking rate of the fruit bag, and the content during the fruit enlargement period was higher than that during the color conversion period. The flavonoid content of bagged ''Nongda 7'' was significantly higher than the control only at a 30% light-blocking rate, and the content during the fruit enlargement period was significantly lower than that during the color conversion period. The content increased gradually with the increase in light-blocking rate during the fruit enlargement period, while it first decreased and then increased during the color conversion period. 【Conclusion】 Bagging can effectively improve the sugar, acid, and flavonoid contents of C. humilis fruits. Furthermore, bagging during the fruit enlargement period is suitable for ''Nongda 6'', while bagging during the color conversion period is more effective for ''Nongda 7''. Both varieties show the best overall improvement in sugar, acid, and flavonoid contents with a 55% light-blocking rate on the fruit bag.