The earthquake with magnitude 8.1 occurred in Gorkha County,Nepal on April 25,2015,following strong aftershocks,caused serious casualties and property losses in northern Nepal,with buildings in the disaster area severely damaged. In this paper,the seismic damage investigation data and satellite remote sensing image were used to conduct remote sensing interpretation,in order to get the remote sensing-based seismic damage index. Then by comparing site point intensity from investigation and assessment in the field with remote sensing seismic damage index,we obtain the fitting transformation relation between remote sensing seismic damage index and actual seismic damage index. Then we estimate the seismic damage index and seismic intensity of full interpretation. The estimated intensity is in good agreement with the field survey results. Our results provide a reference for the transformation model of seismic damage index that can be used for disaster evaluation by remote sensing for earthquakes in this area in future.