This study focused on the behaviour of the frame-supported grid light-weight slabs (FSGL slab) with different forms under low-cycle reversed loadings. Compared with the existing evaluation models showing different damage performances, a damage model was proposed for the FSGL slab system. The mechanical properties of the FSGL slab system were investigated by OpenSees simulation, and the corresponding mechanical parameters were obtained to verify the proposed damage model. Meanwhile, the range of damage index value corresponding to the cumulative damage stage was provided. Furthermore, on the basis of test results, the cumulative damage of FSGL slab system at each stage was described by ANSYS software. Finally, the post-repair recommendations for FSGL slab system were given.