Abstract: The multi-grid composite wall has unique structural types, and its stiffness can be adjusted according to different anti-seismic requests and complex architectural styles. In the context of the frame-shear wall structure, the cooperative work mechanism and shear-sharing ratio calculation method of frame-composite wall structures are studied systematically in this paper. Based on the fundamental theory of Timoshenko beam, the frame-composite wall structure is treated as double anti-seismic system consisting of shear type frames and shear-flexural type beams. The fundamental differential equation is established by the continuous approach, and its analytical solution of displacement and internal force are derived. Based on typical multi-ribbed composite walls test data, the stiffness degradation model of composite wall is established, and stiffness degradation coefficient at different stages is quantified. Then the practical computational method of earthquake shear-sharing ratio on the frame-composite wall structure is put forward, and the dependence of internal force distribution on the composite wall rigidity degeneration is discussed through concrete examples.