The relationship between phytoplankton abundance, Chl a concentration and environmental factors was analyzed on the investigation data in the Southern Ocean during 1989-2009. In the sea area near Prydz Bay, the water abundance of phytoplankton cells was 3.9×104 ～2.83×105 cells/dm3, and the average water abundance of phytoplankton cells was 7.38×104cells/dm3. In the net samples, the dominant species were Fragilariopsis kerguelensis, Fragilariopsis curta, Pseudo-nitzschia lineola, Eucampia antarctica, Thalassiosira antarctica, Corethron criophilum, etc. In the water samples, the dominant species were Fragilariopsis curta, Pseudo-nitzschia lineola, etc. The regression statistical analysis showed the phytoplankton cell abundance was in significant positive correlation with water temperature, DO, and Chl a, and significant negative correlation with PO43- and NO3-.