Dongjiangkou and Zhashui granites are located in southern Shangdan fault of the south Qinling Mountains. Samples were collected from porphyroid granites. The systematic mineralogical characteristics of Dongjiangkou and Zhashui rocks and the rocks-forming p-T estimates were investigated by means of petrological observation, electron microprobe analysis and scanned electron microscope (SEM). The results demonstrate that porphyroid granodiorite and porphyroid granite are composed of quartz, plagioclase (oligoclase), K-feldspar, magnesiohornblende and magnesian biotite,whereas the accessory minerals include zircons, sphene, magnetite and apatite. It can be inferred that the variations of magma composition account for the zoned structure and rapakivi texture in minerals. Zircon in Dongjiang and Zhashui granitoids crystallized when the magma temperature varied in the range of 759～784℃ (771℃ on average). The rare earth elements were saturated in magma when its temperature reached 741～800℃ (773℃ on average). Plagioclase crystallization when the magma temperature varied from 624℃ to 641℃ (632℃ on average), whereas hornblende crystallized when the magma temperature was in the range of 610～668℃ (632℃ on average). The probable emplacement depth of the rocks was ～5.8 km, with the corresponding pressure being about 1.77×10⁸ Pa.