Abstract: A method of examining the purity of dendrimers is revealed. It comprises steps of measuring a light scattering intensity of a set of pure standards having a specific molecular weight with a static laser light scattering detector by use of flow injection polymer analysis; establishing a scaling relation by doing a regression of a ratio of the light scattering intensity per concentration (I/c) against molecular weight (M.W.); measuring the light scattering intensity of a dendrimer to be tested having the same unit and surface-modified functional group as the set of pure standards, and examining the purity of the dendrimer to be tested according to the scaling relation.