Abstract: Fractal is locally similar to the whole in some way.Alteration is a feature of geology,as the remote sensing anomaly in remote sensing image,the pixel brightness and area mode also meet certain fractal theory.Fractal theory can be used for remote sensing alteration anomaly extraction and classification,this method can compensate for the threshold method and the method of gray histogram of visual to determine the inadequacy of method of point mutation.This paper takes Yemaquan area of skarn type copper polymetallic deposit in Qinghai as the study area,drawing iron stain alteration information via ETM data of the research area,analysis the correlation between alteration information and regional metallogenetic.