A model for the bending and twisting deformation of the giant magnetostrictive cantilever is established in the framework of the principle of minimal free energy and four-parameter bending regime. The angular and magnitude dependence of the torsion and flexion response on the external field was discussed for cantilever beam. The torsion behavior of the cantilever is very sensitive to the external field and shows a hysteresis. Furthermore, the torsion hysteresis of the cantilever calculated by our model qualitatively agrees with recent experimental result, which suggests that our model is effective in describing the cantilever system with magnetic anisotropy.