Grain shapes of dynamically recrystallized quartz in ductile deformed rocks, characterized by fractal dimension, are statistically self-similar. The fractal dimensions of dynamically recrystallized quartz grains, decreasing with deformation temperature and rising with strain rate, can be an indictor for the deformation condition. Two methods of polygon and area-perimeter are applicable to calculate the fractal dimension of dynamically recrystallized quartz grains. Grain shapes of dynamically recrystallized quartz in mylonites within Qingyi ductile shear zone show statistical self-similarity, in which numbers of fractal dimension are from 1.228 to 1.326 and paleo-strain rates vary from 10-7.6 to 10-8.7 s -1 . Qingyi ductile shear zone experienced deformation under the conditions of green_schist facies and medium strain_rate.