Objective To investigate clinical value of arginine stimulation test to estimate the first-phase insulin release of pancreatic isletβ-cell and evaluation indicators of insulin release.Methods Choose inpatients with diabetes in the department of endocrinology,divide into type 1 diabetes mellitus group (T1DM group)12 cases,type 2 diabetes mellitus group a (T2DMa group,duration of no more than 1 year)57 cases and type 2 diabetes mellitus group b (T2DMb group,more than 1 year),82 cases.Theserum levels of blood glucose (PG),insulin (INS)and C-peptide (CP)were determined at fasting 0 mi-nutes and 2,4,6 minutes after arginine stimulation,and process the results statistically.Results After arginine stimulation, three groups of PG and the T1DM group of INS and CP had no obvious change and there were no statistical significance (F=0.150~0.696,P>0.05).In T2DMa group and T2DMb group,the peak level of INS and CP appeared at 2nd minute,and those in T2DMa group were higher than those in T2DMb group and these were statistical significance (F=12.145~40.518,P<0.01).The serum levels of INS and CP decreased gradually at 4,6 mintues,but still higher than those of 0 mint-ues.△INS and △CP in T2DMa group were higher than those in T2DMb group,those in T2DMb group were higher than those in T1DM group,and these were statistical significance (F=11.022~10.387,P<0.01).In T1DM group,△INS and△CP had no correlation (r=0.428,P>0.05).In T2DMa and T2DMb groups,those had positive correlation (r=0.768, 0.722,P<0.01).Conclusion Arginine stimulation test can be sensitively estimated the first-phase insulin release of pancre-atic isletβ-cell and that has certain clinical application value.△INS and △CP can be used to evaluating insulin release.