Various mimetic enzymes have been systematically studied concerning the color reaction for hydrogen peroxide oxidizing 4-aminoantipyrine (4-AAP) and N,N-diethylaniline (DEA) to yield a dye. The results have shown that β-CD-hemin is the best mimetic enzyme for peroxidase among those tested, and that DEA is a quite good substrate for β-CD-hemin. Meanwhile, the chromogenic reaction rate and sensitivity of 4-AAP-DEA-β-CD-hemin system for determination of hydrogen peroxide were investigated. Zero to 8.4×10–5 M hydrogen peroxide was determined with good accuracy and reproducibility. The molar-absorption coefficient of the chromogenic compound for hydrogen peroxide determined was found to be 1.65×104 mol l−1 cm−1.