Abstract: The total DNA amount in a cell nucleus varies with different species, the species DNA ploidy can be determined according to the analysis of the DNA content of the cell by Flow Cytometry. In the present study, the DNA ploidy determination for hybrid abalone(♀Haliotis discus hannai×♂Haliotis discus discus)was studied. The cells suspension was provided from small tentacles of hybrid abalone, then the staining was conducted by Destination Access Point Identifier(DAPI), and finally, DNA ploidy determination was finished by PA-Ⅱploidy analyzer. The results showed that the optimal time for oscillation was 1.5~2.0 minutes, the optimal staining time was 4.0~5.0 minutes.