Abstract: The Bacterial pathogens were isolated from the diseased Eriocheir sinensis , which were cultured in the ponds in Shanghai Municipality and Jiangsu Province .The main symptom of diseased Eriocheir sinensis was the appearance of ascites in its abdominal cavity .By the experiments of artificial infection , physiology and biochemistry , the pathogens were identified as Aeromonas hydrophila and Vibrio mimicus .The results of drug sensitivity tests showed that Ciprofloxacin , Norfloxacin and Chloramphenicol were the most sensitive drugs .