Abstract: Objective: To investigate the changes of the function of pancreatic island and insulin resistance(IR) in cases with impaired fasting glucose(IFG) received different interventions.Methods: A total of 127 patients with IFG were divided randomly into three groups to be administrated with different interventions:life style intervention group(received dietary therapy and exercise training,n=41),plus metformin group(received dietary therapy and exercise training and metformin,n=45) and plus rosiglitazone group(received dietary therapy and exercise training and rosiglitazone,n=41).The body mass index,fasting plasma glucose,2 h plasma glucose,fasting insulin and 2 h insulin were measured both before and after the interventions.Finally,glucose tolerance tests recheck were and the changes of insulin resistance and pancreatic island function of each group were compared.Results: The rates of transformation of IFG to diabetes mellitus every year in plus metformin group(6.7%) and plus rosiglitazone group(7.3%) were significantly lower than that of life style intervention group(P<0.05).There were significantly improvements of insulin resistance in both of the two plus groups.Conclusions: The morbidity of IFG is closely related to the IR.Metformin or rosiglitazone can efficiently improve the IR and reduce the transformation of IFG to diabetes mellitus.