For dye-sensitized solar cells (DSSC), the material properties and design parameters of their photoanodes have a more significant impact on the performance of DSSCs. In order to investigate this issue in depth, this paper adopts numerical simulation to explore the detailed impact of change in the photoanode structure on the performance of DSSC. However, the current mathematical model is not comprehensive enough and the prediction accuracy is low. Therefore, based on the theory of photoelectron transfer and Lambert Beer's law, this paper introduces the influence of porosity on electron diffusion coefficient into the mathematical model of DSSC using constant stacking method and variable stacking method, and establishes a more comprehensive and accurate electron transfer model. This model can deeply analyze the impact of changes in the structure parameters of the photoanode on the performance of DSSC. The performance of DSSC under different pore volumes, electron lifetime, SnO2 coating thickness, and specific surface area were simulated through numerical simulation. The results show that as the pore volume of SnO2 thin films increases, the short-circuit current density of solar cells gradually decreases, while the open circuit voltage shows an increasing trend, leading to a gradual decrease in photoelectric conversion efficiency. When the pore volume reaches 0.10 cm3/g, its photoelectric conversion efficiency reaches 5.16%. Therefore, while ensuring the rigidity of the battery, reducing the pore volume of SnO2 as much as possible is beneficial for improving the absorption coefficient and diffusion coefficient. The improvement of these two parameters is conducive to the overall performance of DSSC. At the same time, the extension of electron lifetime will bring about an increase in the short-circuit current density and open circuit voltage of solar cells, thereby improving the photoelectric conversion efficiency. When the electron lifetime reaches 200 ms, its photoelectric conversion efficiency reaches 5.82%. This study provides strong theoretical guidance for optimizing the photoanode structure and improving the photoelectric performance of DSSC through detailed numerical simulation analysis, which helps to further promote the research and application of dye sensitized solar cells.