Researchers at both home and abroad divide mica minerals into two or three categories, which are named highAl, mediumAl and lowAl sericites based on wavelength of spectral AlOH absorption. Although some concern was paid on their minerageny, no systematic specific study has been carried out. With CASI/SASI airborne hyperspectral data obtained for the Xuemisitan area, and based on implementation of mineral mapping, a systematical comparison study was conducted on origins of highAl, mediumAl and lowAl sericites. Based on field geological observation and sampling in the Xuemisitan area, this study analyzed samples of three kinds (highAl, mediumAl and lowAl sericites) of altered rocks using hyperspectal measurement, AlOH absorption wavelength calculation and statistics, microscope observation of thin section, X ray diffraction of bulk rock, and X ray diffraction of clay minerals. In combination with fluid metallogenic theory and minerageny, this study also analyzed their forming mechanism. The results show that highAl sericite underwent intensive alteration and altered minerals of mica include sericite and illite, accompanied by pyrophyllite and finegrain quartz. By contrast, lowAl sericite underwent medium alteration, and altered minerals are dominantly illite and andreattite, and more chlorite, with minor laumonite. HighAl sericite altered rocks contain relatively higher contents of quartz and clay, but relatively lower contents of Kfeldspar, plagioclase and calcite than that of the lowAl series. LowAl sericite altered rocks contain low contents of quartz and clay, but relatively high contents of plagioclase, Kfeldspar and calcite. Combined with detailed mineralogy studies, this study concludes that the highAl sericite identified by hyperspectral may form in the hydrothermal fluid environment with comparatively high temperature and slight acid and the lowAl sericite formed in fluid environment of comparatively low temperature and slight alkaline. This understanding is of great significance for application of hyperspectral mineral mapping information and interpretation of deep exploration information.