The Shapinggou molybdenum deposit in Jinzhai County of Anhui Province is situated in the Qinling-Dabie orogenic belt, with mineralization substantially hosted in monzonitic granite porphyry, syenite porphyry and granite porphyry. Microscopic observation shows that the rocks mainly consist of plagioclase, potassium feldspar, biotite and quartz. With these minerals as the study objects, the authors used electron microprobe technology to analyze their mineralogical characteristics, and the results show that, in the rocks, the plagioclase is albite, K-feldspar is mainly perthite, and biotite is Mg-biotite rich in Mg, Al and K and depleted in Ca, with MF changing from 0.65 to 0.72. Chemical composition of biotite suggests that the intrusion is I-type granite, which is a sort of calc-alkali orogenic granite, materially sourced from both the crust and the mantle. Biotite geothermometer and geobarometer imply that the intrusion was consolidated at 500～580℃, with the oxygen fugacity ranging from 10^-14 to 10^-15.8 and the iron index being a good indicator for molybdenum mineralization.