Abstract: Objective: To analyze the correlation and clinical significance between the serum level change of CA199 and glucose control level of patients with type 2 diabetes.Methods: The levels of serum CA199, fasting plasma glucose (FPG),plasma-glucose postprandial 2 hours(2hPG)and glycosylated hemoglobin(HbA1c)of 120 healthy persons(control group)and 172 patients with type 2 diabetes(diabetes group)were detected.All parameters of diabetes group were measured 3 months after treatment again.Results: The levels of serum CA199,FPG,2hPG and HbA1c of diabetes group were significantly higher than that of cotrol group, and the CA199 level was positively related to the levels of FPG,2hPG and HbA1c,which relation coefficient was 0.444 3,0.493 9,0.515 0, respectively (P＜0.01).The levels of CA199,FPG,2hPG and HbA1c of diabetes group decreased 3 months after treatment, and which difference was statistically significant(P＜0.01).Conclusions: The serum level of CA199 of type 2 diabetes is significantly higher than healthy person, and which exists significant positive correlation with the levels of FPG,2hPG and HbA1c.