In order to improve the efficiency of tunneling oxide passivated contact (TOPCon) cells, a p-type tunneling oxide passivation contact structure was fabricated on the front of N-type TOPCon cells through high-temperature diffusion, improving the emitter passivation performance and reducing front metal recombination. The effects of different deposition time, drive-in temperature, drive-in time and other process parameters on the passivation performance and doping curve of experimental samples were investigated. The experimental results show that when the deposition time is 1 500 s, the drive-in temperature is 920 ℃, and the drive-in time is 20 min, the boron doped polysilicon layer can achieve better passivation performance and boron doping concentration, with the doping concentration of sample polycrystalline silicon layer reaching 1.40×1020 cm-3. The implied open circuit voltage(iVoc) is greater than 720.0 mV. The photoelectric conversion efficiency of TOPCon cells prepared based on this parameter can reach 23.89%, corresponding to a short-circuit current density of 39.36 mA/cm2, the open circuit voltage (Voc) is 726.4 mV, and the fill factor (FF) is 83.54%