Objective: Carbohydrate antigen 125 was reported to be related with incident type 2 diabetes risk and coronary artery calcification. However, little was known about its role in diabetic retinopathy. This study was to analyze the relationship between carbohydrate antigen 125 and diabetic retinopathy in type 2 diabetes. Method: Type 2 diabetes people hospitalized in the department of Endocrinology without a history of tumor from March 2018 to February 2019 were enrolled. Diabetic retinopathy was diagnosed on the results of fundus photography. Serum carbohydrate antigen 125 was measured. People with cataract, other retina diseases, neoplastic diseases, cancers, hepatic failure and renal failure were excluded. Results: All the people were divided into two groups based on the results of fundus photography. There were 177 people with diabetic retinopathy and 291 people without diabetic retinopathy. There was no significant difference in age, body mass index, fasting glucose, and lipid profiles between the diabetic retinopathy group and nondiabetic retinopathy group (p>0.05). There was significantly different in gender, duration of diabetes, hypertension, HbA1c, and urinary albumin excretion rate (pDisclosure G. Yang: None. Funding National Natural Science Foundation of China (81471009); Beijing Health System, Health and Technical Personnel of High Level Plan (2014-3-013); Capital’s Funds for Health Improvement and Research (2016-2-2054, 2020-026285-000005)