For traditional flow cytometry, it is necessary to solve the problem of cell subcellular morphological recognition and the change of cell activity by fluorescence staining. According to the physical characteristics of lymphocytes and eosinophils, the model of particle-free eccentric sphere cells and the dual-core cell were established. Afterwards, based on the simulation experiment software of light scattering theory, a simulation experimental light path which can receive both forward and backward scattered spectra of cells was designed. The scattering distribution of the cell model was obtained, and the relationship between the light intensity and the incident wavelength was established under the relative refractive index of the nucleus and cytoplasm. Through the analysis of the characteristics of the forward and backward scattered light spectra, it was found that the forward scattered light signal was set as X-axis, the cell backward scattered light signal was set as Y axis, lymphocytes and eosinophils had distinct classification characteristics so that a classification method for lymphocytes and eosinophils was proposed. Finally, the method of classifying and counting in this paper has some potential application value for designing all optical, non-invasive and unmarked blood cell analyzer.