Abstract: In order to study part of the biological characteristics of yak-derived Pasteurella multocida rpoE gene in Tibet-Pm1 strain, the experiment used homologous recombination technology to screen out the rpoE gene deletion strain Tibet-Pm1-ΔrpoE, and to analyze the differences between the deletion strain and the original strain Tibet-Pm1 in external environment growth, environmental stress survival rate, biofilm formation, cell adhesion and pathogenicity. The results showed that the rpoE gene deletion strain Tibet-Pm1-ΔrpoE was successfully constructed by homologous recombination technology. The average OD₅₉₅ value of the deletion strain was 0.135, which was significantly lower than the average OD₅₉₅ value 0.337 of the Tibet-Pm1 strain（P＜0.05）. At 20 ℃, the growth of the deletion strain was slower, and the growth of the two strains was significantly different; the difference of the growth of the two strains within 3 h at different temperatures was small. Under UV irradiation, the survival rate of strains with rpoE gene deletion decreased from 21.3% to 16.7%（P＜0.05）; under heat stress condition, the survival rate of strains decreased from 0.75% to 0.59%（P＞0.05）. In the cell adhesion test, the adhesion of Tibet-Pm1 strain in MDBK after deletion of rpoE gene decreased from 6.67 × 10~5 cfu to 1.20 × 10~5 cfu（P＜0.05）. There was no significant difference in the adhesion of the two strains in PK15 cells（P＞0.05）. All the rabbits challenged died within 11 hours, but the average survival time of the rabbits challenged with the Tibet-Pm1-ΔropE strain was longer. Necropsy of the challenged rabbits showed congestion or hemorrhage in some tissues and organs, and the dead rabbits had cecum aeration. The results suggested that rpoE gene was a potential virulence factor of Tibet-Pm1 strain, and the deletion of rpoE could restrain the formatin of biofilm and affect its ability to resist the external environment, causing the reduction of adhesion and pathogenicity of Tibet-Pm1 strain.