 Compound danshen dripping pills is a kind of traditional Chinese medicineTCM, consists of Danshen Radix Salviae Miltiorrhizae, Sanqi Radix Notoginseng and borneol. This study is being conducted to evaluate the efficacy and safety of compound danshen dripping pills in patients with diabetic retinopathySyndrome Of Qi-Stagnation and Blood Stasis, when compared with placebo. 