To observe the curative effect of Qihuang Mingmu capsule on treating early diabetic retinopathy (DR) and its influence on visual evoked potentials P100. Methods: To select randomly from 120 early DR patients who either treated in ophthalmology outpatient department or inpatient department in our hospital from October 2012 January 2015. After numbered them according to their enrollment time, these patients were divided into control group and observation group with a random number tale, 60 cases in each. With the reference to the diagnostic criteria issued by the 3rd Congress of Ophthalmology, it was found that among these patients, there were 37 cases in stage 1, 41 cases in stage 2 and 42 cases in stage 3. The ophthalmic examinations such as visual acuity, fundus fluorescein and visual evoked potential(VEP) were conducted. Results: 1.Before treatment, visual acuity of the observation group and the control group showed no significant difference (P>0.05). After treatment, the observation group vision acuity performed better than the control group (P<0.05), and both groups performed better than before the treatment (P<0.05). 2.The total effective rate of the observation group was 86.67% and control group was 75%. The observation group was better than the control group (P<0.05) by X2 test. 3. Before treatment, the two groups showed no significant difference (P>0.05) in the aspects of VEP P100 latency and amplitude. After treatment, latent time of VEP P100 in the treatment group was shorter than the control group(P<0.05) and its amplitude was higher that that of the control group(P<0.05). 4. After treatment, there are correlations between early DR stages and P100 latency and amplitude. Along with the disease development from stage1 to 3, VEP P100 latency was significantly prolonged (P<0.05) and amplitude decreased obviously (P<0.05). Conclusion: Qihuang Mingmu capsule is effective to treat early DR and can improve vision acuity, also to shorten the latent VEP P100 and improve the P100 amplitude. The VEP P100 can both help to early diagnose DR and to predict its early development.