Objective To investigate the relationship between the serum levels of retinol-binding protein 4(RBP4),blood lipid level and glycemic control in patients with chronic schizophrenia complicated with type 2 diabetes.Methods The levels of glycated hemoglobin (HbA1c),fasting plasma glucose (FPG),cholesterol (TC),triglycerides (TG),high-density lipoprotein cholesterol (HDL-C),low-density lipoprotein cholesterol (LDL-C),apolipoproteinA1 (Apo A1),apolipoprotein B(Apo B),apolipoprotein E(Apo E),lipoprotein(a)[Lp (a)],free fatty acid(FFA),RBP4,fasting insulin (FINS) were determined in 96 patients with chronic schizo-phrenia complicated with type 2 diabetes (schizophrenia group) and 50 healthy subjects (healthy control group),the insulin resistance index (HOMA IR)was calculated.The patients were divided into HbA1c<7.0% group and HbA1c≥7.0% group according to the results of the HbA1c,and the results were statistically analyzed.Results In the HbA1c<7.0% group,the levels of HbA1c,FPG,TG,Apo B,Apo E,Lp(a),RBP4 were significantly higher than those in the healthy control group,the levels of serum Apo A1 and HDL-C was lower than those in the healthy control group (P<0.05).In the HbA1c≥7.0% group,the levels of HbA1c, Body mass index (BMI),FPG,TG,Apo E,FFA,RBP4,FINS,HOMA-IR were significantly higher than those in the HbA1c<7.0% group and the healthy control group,the levels of TC,Apo B,Lp(a)were significantly higher than the healthy control group and the levels of serum Apo A 1 and HDL-C were lower than those in the healthy control group (P<0.05).Single factor Logistic regression analysis showed that BMI,TG,Apo E, FFA,RBP4,FINS and HOMA-IR were risk factors for poor control of blood glucose in type 2 diabetes pa-tients with chronic schizophrenia.Conclusion The levels of RBP4 and blood lipid in patients with chronic schizophrenia complicated with type 2 diabetes may be related to the poor control of blood sugar level.