Based on the optical and semiconductor modules of COMSOL software, the geometric design of spherical silicon solar cell was simulated from the three parts of diameter, spherical defects and anode area. By comparing the reverse saturation current density and the ideal factor, it is found that the smaller the radius of the spherical silicon, the smaller ball defect ratio, the larger the relative contact area of the positive electrode, and the better the electrical properties. The correlation between the geometrical characteristics and photoelectric parameters of the spherical silicon solar cells with different diameters was analyzed, and it was found that there were significant differences between the cells and the conventional planar silicon solar cells.