Abstract: In order to explore the characteristics of pathogenic bacteria within the in-frame of feline sinusitis in the Teaching Animal Hospital of Zhejiang University, in this experiment the contents of frontal sinus, nasal cavity and bullae of sick cats were collected; the isolated bacteria were identified by bacterial isolation and purification, and 16 S rDNA gene sequence analysis; the drug resistance, pathogenicity and genetic evolution of the isolated strains were analyzed by drug susceptibility test, mouse pathogenicity test and whole genome sequence analysis. The results showed that only one strain of Pseudomonas aeruginosa was isolated from the bullae contents of the cat, named ZJU2021. ZJU2021 belonged to a multi-drug resistant strain, and was sensitive to 5 drugs such as levofloxacin, aztreonam and polymyxin B; it was resistant to 30 drugs such as meropenem, vancomycin and doxycycline. The full-length genome of strain ZJU2021 was 6 868 280 bp, encoding 6 426 genes, containing 48 drug-related resistance genes for aminoglycosides, fluoroquinolones, and β-lactams; 61 antibiotic resistance genes producing resistance mechanisms such as antibiotic efflux, antibiotic targeting, and antibiotic inactivation, and 687 genes encoding virulence factors whose products were mainly related to antibacterial activity, iron uptake, regulatory systems, and toxic proteins. The nucleotide similarity of ZJU2021 virulence genes toxA and exoT with the corresponding genes of Pseudomonas aeruginosa in GenBank was higher than 99%. Among them, its toxA and Pseudomonas aeruginosa TJ2019-022 strain（accession number CP065865.1） isolated from Tianjin packaged drinking water were located on the same branch, and the two strains constituted to an independent branch. Its exoT gene was in the same branch as the human-derived Pseudomonas aeruginosa isolated from Beijing, Lanzhou and other place. The results suggested that the strain isolated in this experiment had strong pathogenicity, and the transmission of drug resistance genes between humans and animals would cause serious public health and safety problems. Therefore, clinical monitoring of zoonotic bacterial diseases should be strengthened.