Objective To analyze the influence of hepatosteatosis on pancreatic β-cell function in type 2 diabetes mellitus (T2DM).Methods A total of 213 subjects with T2DM from Metabolic Disease Hospital,Tianjin Medical University from January 2013 to December 2013 were included in the study.Non-alcoholic fatty liver disease (NAFLD) was diagnosed with abdominal ultrasonography.Patients were divided into two groups:T2DM with NAFLD and T2DM without NAFLD.ALT,AST,γ-glutamyltransferase,serum lipid,glycosylated hemoglobin A1 c (HbA1c),fructosamine,fasting glucose,insulin and 2 hours plasma glucose,insulin after 75g glucoseload were detected.The insulin resistance and β-cell function were assessed by HOMA-IR and HOMA-β.Results Among the 213 T2DM subjects,51％ (108 cases) were with NAFLD.The HOMA-IR [4.76 (2.83,7.21) vs 2.79 (1.76,4.37),P ＜ 0.05] and HOMA-β [49.18 (37.78,85.09) vs 29.50 (18.09,45.54),P ＜ 0.05] were significantly higher in T2DM with NAFLD than those in T2DM alone.Within subjects with T2DM and NAFLD,the HOMA-IR [6.28 (2.87,8.17) vs 2.95 (2.07,3.66) P ＜ 0.05] and HOMA-β [59.18 (37.78,85.09) vs 30.59 (28.56,34.49),P ＜ 0.05] levels were higher in subjects with normal liver function than those with abnormal liver function.Conclusions T2DM patients with NAFLD have severer insulin resistance than those without NAFLD.The β-cell function of those patients was compensatory increased,which was decreased in subjects with abnormal liver function.