Abstract: Yulong porphyry copper belt is the biggest in China up to now, and several large porphyry Cu (Mo) ore deposits have been discovered nearby. Altered mineral is one of the crucial indicators for deposit of porphyry Cu ore, alteration information of which can be obtained quantitatively by analysising the remote sensing data. Taking the Hengxingcuo-Yulong-Mangzong belt as the study area, the difference in the results by using ratio method and principal component analysis has been discovered in extracting alteration information which been based on the ASTER data. Through the study found information extraction by the method of spectral characteristics fitting will be provided with the comprehensive. The extraction results can be optimized and screened well by integrating the information of wall rock of deposit, zonal characteristics of circular structure and distribution of alteration information, then those information which were located on the Jiapila and Bolila formation, granite porphyry, in the surrounding of circle structure and alteration information with the characteristics of atolls and band will be more reliable in indicating mineralization.