Objective To observe the effect of Fufang XueShuanTong (FXST) on prevention for retinal microangiopathy of diabetic rats. Methods Take the normal male Wistar rats as normal control group; take the streptozotocin (STZ) Wistar rats as diabetic model group. And then the diabetic model group was divided into two groups: diabetic control group (without other treatment) and FXST treatment group (with FXST at dose 900 mg/kg, by the way of given medicine from esophagus to stomach, 1 time/day, experimental period was 20 weeks). When all the animals had been raised for 20 weeks, not only retinal digesting preparations were used, the endothelium/pericyte ratio (E/P ratio) and micro-vascular changes were observed by microscope, vascular relative area were measured by image system，but also the thickness of capillary basement membrane, the ultrastructural changes of endothelium and pericyte were observed by transmission electron microscope. Results On the 20th week, retinal digesting preparations showed that acellular capillaries, irregular vessel nets, segmental expansion, segmental stricture even occlusion, pericyte number decreased obviously, E/P ratio increased, vascular relative area increased and ghosts of pericytes etc in diabetic control group. Compared to diabetic control group, the retinal changes of FXST treatment group was lighter, the E/P ratio and vascular relative area were closer to normal control group. Transmission electron microscopy results showed that thickness of basement membrane was increased in DM group, vascular changes was light in FXST treated group. Conclusions FXST can prevent the changes of micrangium in diabetic rats effectively. （Chin J Ocul Fundus Dis，2008，24：272-275）