In order to study the damage evolution law of reinforced concrete grid shear wall under earthquake action, the existing two-parameter earthquake damage model of reinforced concrete members is modified, and the earthquake damage model suitable for grid shear wall is proposed. Using the grey incidence method, the test information of grid shear wall is analyzed, the key design parameters are determined, and the formula for calculating the combined coefficient of damage model is given. The effects of shear span ratio, axial load ratio, vertical limb width and transverse limb height on the damage of grid shear wall are studied, and the relationship between the main parameters and the damage evolution of grid shear wall is obtained. Based on the proposed damage model, the damage index of grid shear walls is calculated. According to the damage state of specimens, grid shear walls were divided into five damage levels including basically intact, mild damage, moderate damage, severe damage and collapse failure, and the damage index range of different damage states was calibrated.