Abstract: In order to assay the quality of drinking water,several kinds of brand drinking water on the market and the distilled water offered in the laboratory were studied.By using laser Raman spectrum method,the samples' full width at half maximum(FWHM) and depolarization ratio of laser Raman spectrum at stretching vibration were measured.The study showed that as the samples' mineral substance concentration increased,its FWHM at stretching vibration decreased,but its depolarization ratio of laser Raman spectrum at stretching vibration increased.This results provides us a simple and effective way to assay the quality of drinking water.