The construction scale of concrete face dams is breaking through 200~300 m span in China. It is vital for the seismic performance and safety control of super-high dams to investigate the seismic damage of face slabs. Quadtree cross-scale modelling and non-linear SBFEM-FEM coupling analysis method are introduced to study the fine damage evolution process of high concrete face slab dam under earthquake by combining generalized plastic model of soil, elastic-plastic contact model and plastic damage model of concrete. The results show that the damage zone mainly occurs near the elevation range of 0.6H~0.9H. With the refinement of the grid along the slope, the damage tends to be localized, which can more reasonably reflect the damage phenomenon at the top of the face slab. It is suggested that the size of concrete face along slope direction should be 0.5~1.0 m. Most areas of concrete face can be divided into two or one layers in normal direction, which can satisfy the calculation accuracy. However, for partial area of the slab top, three layers can be considered. The cross-scale analysis method based on Quadtree-SBFEM-FEM achieves the fine damage evolution research of concrete face, which can provide important reference and guidance for the precise location of the weak area of structures under earthquake and the effective analysis of the seismic safety control method.