Presented in this paper is a method of indirect of enzyme linked immunosorbent assay (ELISA) for rapid diagnosis of pathogenic bacteria of Emulsification disease in portunidae.The antiserum for Vibrio alginolyticus was obtained by immunizing rabbit against Vibrio alginolyticus,the antirabbit IgG goat was marked horseradish peroxidase(HRP) and used in an indirect ELISA detection. The result showed that the lowest Vibrio alginolyticus suspension detected limit in laboratory was 10~4 CFU/mL. Vibrio alginolyticus was dectecting in 48h, artificial infection. On worksite, Vibrio alginolyticus was detected by indirect ELISA from the clinically diseased and healthy portunidae at the rate of 90% and 20% respectively, and none from the seawater.