Objective: There are two large ductile shear zones on the sides of the Tongbai—Dabie orogenic belt，and geological scholars have done many studies on the Yindian—Malong shear zone in the south of Tongbai Complex. But there is few study on the shear zone in the northern boundary of the Tongbai Complex. This paper uses many methods to make an in-depth research on the large ductile shear zone in the northern boundary of the Tongbai Complex. Methods：The shear zone in the northern boundary of the Tongbai Complex is a large sinistral strike slip ductile shear zone of the Tongbai—Dabie orogenic belt，which developes mylonite，ultramylonite and straight gneiss. On the basis of the field observations，we make studies on the structural deformation characteristics of the shear zone through the analysis of the mineral composition，the displacement calculation of the shear zone，the fractal dimension of the quartz，and the calculation of differential stress and strain rate of quartz. Results：The results show that the displacement of the shear zone in the northern boundary of the Tongbai Complex is from 38.3km to 41.1km. The correlation coefficient R of the grain boundary of the quartz with dynamic recrystallization is more than 0.96 statistically，the dynamic recrystallization grain boundaries have self-similarity in statistically significant. The fractal dimension is from 1.207 to 1.302，and from the core to the edge of the shear zone，the change of particle size and fractal dimension is gradually becoming larger and larger. The shear zone’s differential stress value is between 23.583MPa and 46.983MPa，and the strain rate is from 1.70×10-11 to 9.74×10-11s-1. Conclusions：On the basis of the detailed field observations and indoor analysis，and by comparing the diameter of quartz with dynamic recrystallization，the differential stress and the strain rate in the shear zone can be found that the differential stress and strain rate showed a positive correlation，both becoming gradually smaller from the core to the edge in the shear zone. But quartz diameter shows a negative correlation with the differential stress and strain rate，as the quartz diameter becomes larger from the core to the edge in the shear zone，the differential stress and strain rate becoming smaller. The larger the difference stress，causes the quartz particle’s strength stronger，the deformation stronger，and the strain rate performs stronger. From the microscopic structure deformation view to study and understand this shear zone is of great significance to reveal the tectonic evolution and to establish the structural model of Tongbai—Dabie orogenic belt.