Abstract: Severe plastic deformation of Cu-Zn alloy was carried out by using room temperature torsion test, and the mechanical properties of Cu-Zn alloy with different torsion turns after heat treatment were investigated by nano-indentation technology. The Yong's modulus, hardness, yield stress and strain hardening index of the Cu-Zn alloy under different torsion turns were calculated based on Oliver-Pharr model and dimensional analysis. The results show that with the increase of torsion turn, the average grain diameter of Cu-Zn alloy decreases. Under the same torsion turn, the axial average grain size of Cu-Zn alloy is smaller than that of radial grain size. The microhardness and Young's modulus of the alloy decrease with the increase of the load. Based on dimensional analysis, the average yield strength of the alloy is 0.099 GPa and the average strain hardening index is 0.26, which is basically consistent with the test results.