Abstract: Objective To explore the application value of serum ferritin in the Type 2 diabetes mellitus (T2DM) patients. Methods Choose from February,2013 to October,2015 in Haikou City People's Hospital of Endocrinology,diagnosis and treatment of patients with T2DM(T2DM group) 120 cases,according to glycated hemoglobin (HbA1c) levels are divided into:the efficacy of good group(A) and efficacy of 53 cases poor(group B) 67 cases,while selecting normal controls(NC) group,60 cases.Serum iron(SI),serum ferritin(SF),transferring(TRF),glycosylated hemoglobin(HbA1c),fasting plasma glucose(FPG) and fasting insulin(FINS) were determined and Calculated Insulin resistance index(HOMA-IR) and pancreatic β-cell function(HOMA β-cell) and compared the changes in T2DM group and NC group,group A and group B of the indicators and analysis of its relevance. Results Compared with the NC group,T2DM group FPG,HbA1c,FINS,HOMA-IR and SF were increased(P<0.05);Compared with group A,SF SF and HOMA-IR of group B all increased(P<0.05),HOMA β-cell decreased(P<0.05);T2DM patients with SF and HbA1c were positively correlated(r=0.584,P<0.05),positively correlated with HOMA-IR(r=0.451,P<0.05),and HOMA β-cell negative correlation(r=-0.468,P<0.05). Conclusion T2DM patients with iron metabolism disorders,iron overload may increase insulin resistance and β cell damage;SF may be an important factor affecting its efficacy,high SF is difficult to control blood glucose.