Abstract: Melting water accounts fro a large proportion in the Tianshan Mountains, where snow and ice provide water resource for many rivers and the ecological environment in the arid areas, so, quantitative monitoring of snow and ice is very important.Based on the spectral characteristics analysis of clouds and snow, the comparison of several common methods of snow information extraction and the actual detection of snow on the upstream of the Manas River, it proves that the method of NDSI is a better technical method than any other method on the use of TM image emtracting snow.