In this study, apple fruit of 'Starkrimson Delicious' was treated with white, purple and yellow transparent bags. This research aimed to explore the effect of light quality difference caused by different color transparent fruit bags on the anthocyanin synthesis mechanism of apple. The results showed that, after color transparent bag treatment, the L^* and b^* values of the apple skin gradually decreased, the a^* value gradually increased, and the color of apple skin turned red quickly. When bagging treated for 14 d, the color was the darkest red, L^* value was lowest, a*value was highest, and b^* value was lowest of apple fruit in purple bags, at the same time, the anthocyanin content from high to low was purple bags, yellow bags and white bags, successively. The activities of PAL, DFR and UFGT enzyme were higher in purple bag fruits, while the activity of CHI enzyme was relatively low. Analysis of gene expression showed that, the high expression level of MdMYB1, MdUFGT, MdUVR8 all appeared on purple bag fruits in later period. Correlation between MdDFR expression level and the anthocyanin content of apple fruit treated with white bags was significantly related, and the same correlation between MdMYB1 expression level and anthocyanin content of fruit in purple bags as MdDFR gene. In conclusion, purple transparent bag can promote the synthesis of red apple anthocyanin, and its effect is better than yellow transparent bag and white transparent bag.