Abstract: A quantitative method of remote sensing for monitoring soil losses introduced briefly and its operations and results of application to small valley of UNDP experimental region is described in this paper. Although form of the model for monitoring soil erosion losses in the method is the same as the RUSLE, the formula and algorithms for model factors are generated from loss data observed in our country. Therefore, it is more applicable to loss regions in our country, and suits personal computer to process data of GIS and remote sensing. The results of its application are more accuracy and useful than those of existing methods for the conventional survey and qualitative remote sensing. The monitoring results of UNDP experimental region show that the quantitative remote sensing method can not only use for big valley (e.g. county or province region), but also use for small valley (≥ 7km²).