Through molecular dynamics simulation, the torsional deformation behavior of copper nanowires in different crystal orientations (Ⅰ: x[1 0 0] y[0 1 0] z[0 0 1], Ⅱ: x[1 0 1/8] y[0 1/8 0] z[－1/8 0 1], Ⅲ: x[1 0 1/4] y[0 1/4 0] z[－1/4 0 1]), different crystal orientation ratios (α₁=1/6, α₂=1/2, α₃=5/6), and different numbers of twin interfaces (0, 2, 4) were studied, as well as the relationship between the shear stress and torsion angle of copper nanowires during torsion. The results indicate that change the orientation type contributes to enhancing the torsional mechanical properties of copper nanowires. Reducing the ratio of internal diameter to external diameter also improves the torsional mechanical properties of copper nanowires. Furthermore, decreasing the number of twin interfaces can strengthen the torsional mechanical properties of copper nanowires. The torsion process of copper nanowires can be divided into three stages: elastic, plastic and deformation failure. The research results provide a basis for investigating the torsion of high?strength copper nanomaterials.