Abstract: The mechanism of Iuminol chemilunesence in hematoporphyrin derivative （HPD） photosensitized oxidation of NADH, after irradiated by 630nm and 514.5nm laser and depressed by indocyanine green, （ICG） was reported. It is found that ICG can decrease the value of chemical light caused by HPD photosensitization. This action depends on the concentration of ICG in the reaction system, but is not influenced by the wavelength of irradiation laser.