Light scattering is an effective method to distinguish normal and diseased red blood cells. However, there is a lack of research on the modeling and light scattering characteristics of diseased red blood cells. Based on the abnormal diffraction approximation theory, this paper constructs the light scattering models of normal double concave pancake shaped red blood cells and diseased oval, sickle shaped and aggregated red blood cells, determines the applicable angle range of this theory[M1]  when applied to red blood cells, and uses numerical simulation to explore the differences in the spatial distribution of light scattering between abnormal morphology, abnormal size and abnormal aggregated red blood cells and normal red blood cells. The simulation results show that there are great differences in the extreme number and corresponding angle of the scattered light intensity curve of red blood cells with different radius and shape, while the angle corresponding to the minimum value of the scattered light intensity curve of aggregated red blood cells is basically the same, and the minimum value has a gap of more than 22%. This conclusion is of great significance for detecting and distinguishing normal and diseased red blood cells by light scattering method and establishing an algorithm for retrieving the morphological characteristics of red blood cells.