The present paper presents a new alteration mineral mapping method based on statistical analysis of field measured spectra. First of all, this method processes a cluster of measurement data of spectra of field samples, in order to distinguish different sample area from the overall types. Second, the results of the clustering of different mineral alterations established their respective discriminant functions. Thus, mapping major alteration type accords with the clustered reference spectra by given remote sensing images. Finally mapping further alteration types was based on the discriminant function of second step, which leads to final alteration map. This method takes full account of the different combination of alteration types, as well as the regional differences of alterations, and the establishment of the discriminant function for alteration minerals is more scientific. Moreover, the authors accessed the reliability of mapping to a certain extent. The method was applied to a study area of Baogutu in Xinjiang Province, which represents a good result.