Objective To examine aerolysin gene in Aeromonas hydrophila and analyze the percentage of bacterial isolates carrying aerolysin virulence gene. Methods After Aeromonas hydrophila were isolated and identified by routine method,aerolysin virulence gene was amplified by PCR,and the percentage of bacteria lisolates carrying aerolysin virulence gene was calculated. Results Aerolysin virulence gene was found in 5 strains of Aeromonas hydrophila,and the percentage of bacterial isolates carrying aerolysin virulence gene was 50%(5/10). Conclusion Aerolysin virulence gene is one kind of important virulence factor of Aeromonas hydrophila.