Abstract: In this study, the simulated samples used were compounded with pure culture bacteria and NaCl water. Sterilized 0. 85% NaCl water served as the blank control, selecting water vibrio and colon bacillus served as pathogen negative control. This study compared the distinguishing power of three assays from the order for them to enter thediscriminant model, the validity evaluation, and ROC curv e area of them. The results obtained indicated thorder of three assays to enter the discriminant model was: PCRtest→bacterial culture→agglutinate test. Taking thediscriminant classification as the reference test, the sensitivity of PCRtest reached 100% and the specificity 100%, the sensitivity of bacterial culture reached 100%, the specificity 96.5% and the false-positive rate 3. 45%, and the sensitivity of agglutinate test reached 64.77%, the specificity 96. 55%, the false-positive rate 3. 45% and the false-negative rate 35. 23% . The order of ROC curve area from large to small was* PCRtest(0. 9617)> bacterial culture(0 9596)> agglutinate test(0. 6334). So, the order of the distinguishing power of three assays from large to small was: PCR test> bacterial culture> agglutinate test, the diagnostic accuracy of PCRtest was higher than the other two assays.