In this research, hydrothermal alteration areas include phyllic, argillic and propylitic that are associated with Cu-Au porphyry mineralization are investigated by various methods of processing ASTER data. These methods are False Color Composite (FCC), Band Ratio (BR), Principal Component Analysis (PCA), Matched Filtering (MF) and Least Squares Fit (LS-Fit). Optimum Index Factor (OIF) method was then used to select the best color combinations. Comparing the results of different methods with the data of 1:10000 geological map, indicates that recognized alteration areas of remote sensing data have an acceptable agreement with those of the geological map. It was also found that the LS-Fit method is the best method for separating of alteration areas in the region.