This paper presents a feasibility study of using bacteriophage to detect penaeid shrimp luminous disease pathogen,Vibrio Harveyi.The results indicated that the Vibrio harveyi bacteriophage separated from shrimp hatchery showed a special phagocytosis on Vibrio harveyi.They could not infect and lyses certain bacteria such as Vibrio alginolyticus,Vibrio parahaemo-lyticus and photosynthetic bacteria,but could specially lyse the experimental Vibrio harveyi which were separated from the same hatchery.The appearance rate of engulfing bacteria spot is 80 percent.The appearance rate of engulfing spot showed a high correlativity with the shrimp luminous disease occurrence.The method can be used as a chief means of detecting Vibrio harveyi and diagnosing shrimp luminous disease pathogen.