In the process of obtaining the snow cover area from MSS image with NDSI algorithm

there is a shortcoming that MSS does not have short wave infrared band which can help to distinguish high reflectance of cumulus.To improve the accuracy of obtaining the snow cover area from MSS

this paper explores a method of snow cover mapping based on NDVI background field.Firstly

the land surface reflectance image is derived through 6S model while making radiometric calibration.Then

according to the difference of spectral characteristic and the difference of NDVI characteristic of land objects

we build a Lookup Table on threshold of snow spectrum in the SPECTRAL extension of ENVI software.Through the three demonstrations of ETM+ and TM

the process of algorithm and the way to build LUT are illuminated in detail.And the accuracy of snow cover mapping of this method is tested by NDSI.The results show that the new algorithm has higher Overall accuracy and Kappa Coefficient compared with generally classified method（such as Maximum Likelihood Method）.