Abstract: Taking the case of Ruoergai region as an example, and by means of image processing,in formation extracting and imaga analysing, the writer pointed the identification key of the peat bog area in images of all four MSS bands, which shows a dark tone with lower reflectance. Accordingto the key, the distribution range of peat resoures in the region was exactly located. Using the spectrum measorements of ground body and the correlation analysis,the forming mechanism, reliability and universal suitability of the identification key were expounded. The technical key and scientific basis were provided for the application of remote sensing technique in surveying peat resources.