On the basis of experiment on friction sliding of simulated fault gouge, the authors carried out the observation and analysis of the SEM microstructure about the mineral samples of plagioclase and pyroxene, which were the two main gabbro composition and were based on the experiment, for the purpose of understanding fault activity in deep crust. The boundary shear, R1‐shear and Y‐shear planes were well developed in the plagioclase simulated fault gouge, but P‐, R2‐ and X‐shear planes were scarcely observed. The boundary shear plane and R1‐shear plane were developed in pyroxene shear zone. However, the effect extent on the sliding features of gabbro through the study of the above two minerals remain to be further proved.