Inclusion Criteria:  1. Patients with the diagnosis of type 2 diabetes. 2. Patients with the diagnosis of non-proliferative diabetic retinopathy and the classified as mild and moderate. 3. Target eye best corrected vision acuity (BCVA) ≥ 34 points (ETDRS vision chart, vision equivalent of score 20 / 200, decimal 0.1). 4. Patients who meet the syndrome differentiation standards of yin asthenia generating intrinsic heat and eye collateral stasis in traditional Chinese medicine. 5. HbA1C ≤ 9%. 6. Age between 18 and 75 years old 7. Informed consent, voluntary subject. The process of obtaining informed consent form complies with Good Clinical Practice(GCP).  Exclusion Criteria:  1. Patient with the diagnosis of diabetic retinopathy is combined with severe vitreous blood effusion, or required total retinal laser treatment or vitrectomy. 2. Patient who has been treated with full retinal laser photocoagulation. 3. Patient with difficulty in evaluating fundus images with refractive medium turbidity. 4. Patient was diagnosed of acute metabolic disorders such as diabetic ketoacidosis or combined with severe acute infection in the past 1 month. 5. Patient with other serious diabetes complications, such as diabetes gangrene. 6. Patient was allergic to Tangningtongluo tablets, or Calcium dobesilate, or its composition. 7. Female patient with pregnancy, or prepare for pregnancy, or lactating. 8. Patient with serious cardiovascular, liver, kidney or hematopoietic system disease, and mental diseases. 9. Liver and renal function (Alanine aminotransferase (ALT) or Aspartate aminotransferase (AST) above 2 x Upper limit of normal (ULN)and Cr> above 1 x Upper limit of normal (ULN)). The diabetic nephropathy stage was 4 and above. 10. Patient with eye diseases such as glaucoma, uveitis, optic neuropathy, and severe cataract. 11. Patient participated in other clinical researches within a month.