Abstract: In this paper a low-doping concentration p-n junction was prepared by low-pressure three-step diffusion method for p-type single crystalline silicon passivated emitter rear contact（PERC）solar cells combined with narrow finger gap. The sheet resistance of the silicon wafer after phosphorus diffusion can be adjusted by varying the nitrogen flow rate in the second step. As the doping concentration decreases at the emitter surface,the sheet resistance increases as well as less Auger recombination and increasing of average minority carrier lifetime. The doping concentration and junction depth of samples were measured by ECV test. Given the theoretical analysis of the emitter photoelectric loss,the optimized sheet resistance of 180 Ω/□ for thermal diffusion was determined with the finger number of 114. As indicated by the cell performance in in-line process,the short-circuit current is stably increased by 80 mA due to the enhanced short-wavelength response with high sheet resistance. The fill factor is maintained due to the narrower finger gap due to the enhanced collection of photo generated carrier. The stabilized conversion efficiency was improved by 0.28% reaching 22.30% was achieved for inline PERC solar cells production.