The substrate specificities of glutathione peroxidase (GPX)mimic, 6,60-ditellurobis(6-deoxy-b-cyclodextrin) (6-TeCD), for three hydroperoxides (ROOH), H2O2, tertbutyl hydroperoxide (t-BuOOH) and cumene hydroperoxide (CuOOH), are investigated through molecular dynamics (MD) simulations. The most stable conformations and the total interaction energies of complex of 6-TeCD with ROOH are used to evaluate the substrate specificity of 6-TeCD. The steady-state kinetics of 6-TeCD is studied and the Michaelis-Menten constant (Km) and second-order rate constant kmax/KROOH showthat 6-TeCDdisplays different affinity and specificity to ROOH. These results of experiments are well consistent with ones obtained by MD simulations, indicating that MD simulations could be applied to evaluation substrate specificity of small-molecule enzyme mimics.