Snow is one of the major sources of water in most parts of the world. Hydrology and climate studies determine that the snow cover surface area to be one of the important parameters of snow. One of the tools that has lots of uses in the watershed snow cover survey and hydrological properties is remote monitoring by satellites images. MODIS imageries compared with other images like NOAA has better spatial resolution and more bands and is better for this surveying. Therefore in our study for mapping of snow cover we used MODIS images and NDSI indicators. In the snow mapping algorithm, at the first stage the NDSI index snow was isolated but for discrimination between snow and other wet lands we used the thresholds in 2, 4 and 6 bands. The results showed that the NDSI index in conjunction with the thresholds has appropriate effects for this purpose. In this research, the average error of snow cover maps including the error NDSI index was less than 20 percent.