Abstract: This study isolated and purified a virulent bacteriophage, named Ph-0, from lake by pathogenic Aeromonas hydrophila of Procambarus clarkii. The biological characteristics of the isolated bacteriophages were analyzed, including plaque morphology, the optimal multiplicity of infection, one-step growth curve, and thermal stability. The results showed that the plaque of phage Ph-0 was round with a semitransparent halo on the edge; the optimal multiplicity of infection was 0.1 MOI; the one-step growth curve showed that the incubation period of bacteriophage was about 20 minutes and the lytic period lasted about 70 minutes; the activity of bacteriophage had no obvious change from 0 to 40℃. The activity of bacteriophage did not change significantly between 0 and 40℃, but began to decrease at temperature above 50℃. It was stable in both acidic and alkaline environment, and the activity of bacteriophage was extremely sensitive to UV and chloroform. The results showed that the protective rates of injection and immersion were 66% and 20% respectively. The results of pathological sections showed that the gills, heart and hepatopancreas of Procambarus clarkii after phage treatment were greatly protected. The above results showed that bacteriophage Ph-0 is a bacteriophage with strong lytic ability and short lytic cycle, which has a certain protective effect on Procambarus clarkii.