Based on an analysis of the spectral characteristics of surface objects and using ETM remote sensing image，the authors utilized PCI software and employed the mask technique to remove various kinds of disturbance information such as white mud ground，water body， shadow and vegetation. With principal component analysis， band ratio and threshold segmentation techniques, the information of iron staining and hydroxyl alteration in Qangdoi area of western Tibet was extracted. In accordance with the obvious anomalous areas, the reference spectra were built up. The method of spectral-angle mapper was used to remove the pseudo-anomaly  information. In conjunction with the characteristics of linear structure in the study area， the metallogenic prognosis was carried out and，as a result, the prospect areas were delineated. The method for metallogenic prognosis proposed in this paper is fairly flexible and effective，and can provide a reference and effective way for speeding up the geological exploration work in future.