Remote sensing alteration zoning information of the Dexing porphyry copper deposit was extracted by using ASTER data. The main alteration minerals of the alteration zone in the Dexing porphyry copper deposit include muscovite, illite, chlorite and calcite, dolomited by characteristics of alteration minerals. According to the spectral characteristics of main alteration minerals, their remote sensing anomaly information was extracted by using four extraction methods: the ratio, the slope, the related absorption and the principal component analysis, and the information of each remote sensing alteration zone was extracted with the superposition method.