Abstract: The high-rise frame-diagrid structure is a new dual system. It is composed of a high-rise diagrid structure and a frame structure. The horizontal shear-force distributions under elastic and plastic states are studied by theoretical derivation and numerical simulation. According to the characteristics of cooperative deformation of the diagrid structure and the frame structure, a simplified 2D elastic analysis model is proposed. Formulas for calculating the lateral deformation and the shear force of structures are derived. The shear distribution characteristics of the structure in the elastic state are also studied. The non-linear static Pushover method is used to calculate the structural system. The deformation characteristics, stiffness degradation and shear-force distribution in plastic stage are studied. The results show that the high-rise diagrid structure and the frame structure have good cooperative behaviors. In the elastic state, the eigenvalues of structural stiffness and the load distribution have a great influence on the shear-force distribution of the structure. In the plastic state, the stiffness of diagonal columns will degrade and the shear force will be redistributed.