Objective To localize endogenous alkaline phesphatase in human neutrophils with ELF (enzyme-labeled fluorescence)-97 phosphate, which yields an intensely fluorescent yellow-green precipitate at the site of enzymatic activity. Methods Neutrophils were isolated from human blood and fixed,then histochemistry with the ELF-97 phosphate was performed with the ELF-97 endogenous phosphatase detection kit.All photography was performed with a Nikon labophot fluorescence/DIC microscope. Results Fluorescent yellow-green granules, well-distributed but size-varied, were observed in neutrophils under fluorescence microscope.There were 94.102±3.133 percent rate of positive neutrophil alkaline phosphatase among 51 cases of healthy volunteers.Conclusion ELF-97 endogenous phosphatase detection kit can provide sensitive,high-resolution localization of endogenous phosphatase activity in neutrophils.