This paper presents the background and methods for estimation of surface emissity from the MSU measurements. It shows the results obtained from NOAA-10 MSU data of December 13,1988 at 1050 GMT using the methods discribed in the paper. And the results have a good agreement with Grody's (1983) . Applications of surface emissity are briefly discribed at the end of paper. It can be seen that the different types of surface can be distinguished through MSU surface emissity, and it is possible to observe the flooding areas and sea ice by using MSU surface emissity.