Abstract: Huanghua port plays a very important role in the north economic development of China and also brings seriously threaten to local marine ecosystem. To study the relationship between marine exploitation and phytoplankton communities, the phytoplankton community structure in the Huanghua Port adjacent waters was analyzed based on the results of four surveys during 2017. The influence of environmental factors on the phytoplankton community in the Huanghua port area was discussed using redundancy analysis (RDA). A total of 74 species belong to 35 genera of 3 phyla were finally identified. The dominant species of phytoplankton showed obvious cross and seasonal succession. The abundance of phytoplankton ranged from 19.4×10⁴ to 2095.6×10⁴ cells/m³ over the 4 seasons, the average abundance of whole year was 762.2×10⁴ cells/m³, which was the highest in autumn and the lowest in spring. The Shannon-Wiener diversity index which was the highest in the summer ranged from 2.23 to 2.88. The 15 stations can be separated into four groups (named group Ⅰ, Ⅱ, Ⅲ and Ⅳ) by the Cluster Analysis based on the abundance. Redundancy analysis showed that the most important factors affecting phytoplankton community structure are dissolved oxygen (DO), suspended substance (SS), water temperature (WT), total petroleum hydrocarbon (TPH) and dissolved inorganic phosphorus (DIP) which may promote or inhibit the growth of specific species. In addition to paying attention to the production processes such as desilting and the discharge of pollutants from ships at Anchorage, Huanghua port should also strengthen the monitoring of the nearby rivers entering the sea, which may cause great change of phytoplankton communities structure and even red tide or other ecological disasters.