Abstract: The rot caused by fungal infection is the main factor affecting the postharvest storage of Yuluxiang pear. In order to clarify the species and biological characteristics of pathogenic bacteria that cause postharvest rot of Yuluxiang pear, the postharvest pathogenic bacteria were isolated and purified, combining morphological and molecular biological characteristics to determine its species, and to clarify the growth of pathogenic bacteria under different temperature, pH, carbon and nitrogen source conditions. The results showed that: Alternaria alternata, Aspergillus, Penicillium polonicum and Fusarium were the main pathogens causing postharvest rot of Yuluxiang pear. The optimum growth temperature of Alternaria alternata and Fusarium was 25~30 ℃, while the optimum growth temperature of Aspergillus and Penicillium polonicum were 25~35 ℃ and 20~25 ℃, respectively. The optimum growth pH of Alternaria alternata and Aspergillus were 6~10 and 7, respectively, while the optimum growth pH of Penicillium polonicum and Fusarium were both 5~7. The optimum growth carbon sources of Alternaria alternata and Penicillium polonicum are glucose and mannitol, respectively, the optimum growth carbon source of Aspergillus and Fusarium was maltose. The optimum growth nitrogen source of Alternaria alternata, Aspergillus and Fusarium was beef extract, and the optimum growth nitrogen source of Penicillium polonicum was peptone.