23 cases including 45 eyes of diabetic retinopathy treated with nourishing Yin, tonifying Kidney and blood-activating herbs were presented. The results showed that the serum viscosity and cholesterol were markedly decreased (P less than 0.01), and the implicit times of a-wave and b-wave in flash electroretinogram(F-ERG) were significantly advanced than those of themselves before treatment (P less than 0.01 and P less than 0.05 respectively). The visual acuity in most cases was improved and the effective rate was 64.44%. The therapeutical mechanism for diabetic retinopathy used by nourishing Yin, tonifying Kidney and blood-activating herbs were discussed. The authors suggested that the Chinese herbs probably could change the chemical and physical properties of blood, promote the ocular circulation and the absorption of sludged blood and decrease the retinal ischemia.