AIM:To observe the changes of high mobility group box-1 (HMGB-1) in plasma and aqueous humor of patients with diabetic retinopathy (DR) and its clinical significance.METHODS: Research objects were the patients with diabetic mellitus (DM) in the First Hospital of Xi’an Jiaotong University from August of 2010 to December of 2010. According to DR, the patients were divided into non-diabetic retinopathy (NDR) group and DR group. DR group was divided into background diabetic retinopathy (BDR) group, and proliferative diabetic retinopathy (PDR) group according to disease course. Normal control group was set, plasma group with 40 cases and aqueous humor group with 28 cases were collected, and they were analyzed by ABC-ELISA. RESULTS: The levels of aqueous humor HMGB-1 in patients with DM were significantly higher than those in control group (P<0.05). Of patients with diabetes, according to DR course, HMGB-1 concentration had not the obvious difference (P>0.05). HMGB-1 concentration in plasma of patients with diabetes had no obvious difference compared with control group(P>0.05).CONCLUSION: HMGB-1 may play an important role in the occurrence of DR, but it has no obvious relation with DR pathological process.