Abstract: The wall rock alteration information in vegetation-covered areas is weak due to less exposed bedrock. To carry out prospecting work in the surroundings of old mines, after a series of experiments by different methods, the combined technology of vegetation suppression and rock-soil mass spectrum test is finally chosen for alteration information extraction. Firstly, the forcing invariant vegetation suppression technique is used to reduce vegetation interference, then the spectral information of altered wall rock and rock mass in altered zone of the existing mine is collected to establish a spectral sample library in the study area, and finally the extraction of alteration information is completed by CART (classification and regression tree) technique. The experiment results show that the CART alteration information extraction method based on vegetation suppression technique is effective in the extraction of remote sensing alteration information around old mines in vegetation-covered areas.