Tetra substituted amino aluminum phthalocyanine (TAAlPc) has been synthesized and used for the first time as a new red region fluorescent substrate for the determination of hydrogen peroxide catalyzed by peroxidase or mimetic peroxidase. Under optimum conditions, the calibration graph has a linear range of 0.0-3.0×10 -7 mol/L H 2O 2 with a detection limit of 3.7×10 -9 mol/L. The feasibility of TAAlPc as a new promising red region substrate in practical application has been proven in the determination of H 2O 2 in rainwater.The proposed method can largely minimize the interference that results from background fluorescence or scattering light and has a high analytical sensitivity.