Abstract: By using flow cytometry (FCM), plate count and filtration membrane respectively, bacterioplankton abundance, number of Vibrio anguillarum and fecal coliform groups were detected. The correlation between bacterioplankton abundance and the environmental factors was analyzed. The results indicated that the bacterioplankton abundance in seawater was about 3.1 \times 10^8 \sim 3.3 \times 10^9 \mathrmcells / \mathrmL, and the number of Vibrio anguillarum was 2.0 \times 10^4 \sim 6.2 \times 10^6 cells/L. The maximum of fecal coliform group value was 800 cells/L which was lower than the Chinese National Standard of Seawater Quality (\leqslant 2000 cells/ L). The distribution of bacterioplankton was temporal and regional. Meanwhile, we analyzed the correlation between bacterioplankton abundance and the environmental factors, it shown that there was a positive correlation between the bacterioplankton abundance and temperature which was lower than 12 ^\circ \mathrmC in February and May. And there was a positive correlation between bacterioplankton abundance and the environmental factors, temperature, \mathrmNH_4^+, \mathrmNO_3^-, \mathrmPO_4^3-, in August. While the DO value was negatively correlated with the bacterioplankton abundance. In November the content of \mathrmNO_3^- influenced the bacterioplankton abundance most. All the above-mentioned environmental factors might be the primary limiting factors.