The effect of the low energy (1.8 keV) proton radiation dose on the conversion efficiency of mono-crystalline silicon solar cells was analyzed in detail by TCAD semiconductor device simulation software. The relationship between the proton radiation dose and the recombination center density and trap density were given by comparison of conversion efficiency and degradation characteristics. In the case of different proton radiation doses, the effects of front surface field (FSF) structure and front surface floating emitter (FFE) structure on short-circuit current density, open circuit voltage and conversion efficiency of solar cells were analyzed in detail, providing design basis for the front surface structure of solar cells under proton radiation. The simulation results show that the conversion efficiency of the solar cell is almost unchanged with the increase of the proton irradiation dose when the proton irradiation dose is less than 1×109 cm-2.When the proton irradiation dose is constant, there is the optimal doping concentration of FSF and FFE, which makes the solar cell conversion efficiency highest. When the proton irradiation doses are 0 cm-2 and 1×1010 cm-2, the peak conversion efficiency of the FFE structure is slightly lower than that of the FSF structure. When the proton irradiation dose is 1×1011 cm-2, the improvement effect of the FFE structure on the conversion efficiency of IBC solar cells is significantly better than that of the FSF structure.