The study on the absorption spectrum changes of carbinol extraction (pH=3.00±0.01) of litchi pericarp against the natural light within PE bags of different colours (black, blue, green, yellow and white) was made. The findings are that the white PE bags cannot prevent effectively the photolysis of anthocyanidin glucoside of litchi pericarp, but the black, blue, or red PE bags can improve its light stability. This does not only confirm natural lighting effect on litchi browning, but also provides theoretical basis for improving litchi packing bags.