The effects of torsional deformation on the mechanical properties and microstructural evolution of pure copper rods with cylindrical shape have been investigated in this study by twisting the rods by different numbers of revolution. The torsional deformation can introduce gradient hardness along the radial direction due to the formation of gradient grains and dislocation substructures along the radial direction. Tensile testing results indicated that the torsional deformation can significantly enhance the strength of pure copper with consuming the ductility. Due to the large grain size and relative high SFE of pure copper in this study, only gradient grain size and dislocation substructures formed along the radial direction after torsional deformation.