The invention relates to an unfolding finite element modeling method for a complex cylinder structural plane. The method is used for performing structure strength numerical simulation analysis. The method comprises the following steps: establishing a two-dimensional unfolding geometric model of a complex cylinder structure, and then marking plane grids, wherein the quantity and positions of the nodes on the two sides of the plane grids are corresponding to each other; establishing a node shifting function; rolling the plane grids into cylinders; eliminating repeated nodes; perfecting a finite element model, applying material, attribute, loading and boundary conditions, and submitting operation and performing result analysis. According to the invention, the quick and high-precision modeling for the complex cylinder structure is realized; the problem of difficulty in space structure modeling is solved; the method can be widely applied to the finite element simulation analysis for a launcher and guided missile weapon structure, a pressure vessel cylinder structure, an airplane cylinder structure, and the like; the method is especially fit for the complex cylinder structure containing the openings in various shapes, reinforcing ribs, and the like.