Phosphorus is a necessary nutrient utilized by marine phytoplankton. Responses of marine phytoplankton to phosphorus are closely linked with primary production, carbon cycle and nitrogen fixation. The phosphorus pools utilized by phytoplankton are summarized. Phytoplankton prefers dissolved inorganic phosphorus, and can also utilize Dissolved Organic Phosphorus (DOP) by some enzymes in phosphorus deficient regions. Utilization of various phosphorus forms by different phytoplankton species is then compared. Phytoplankton physiology studies explained differences in phosphorus availability to different phytoplankton species. Strategies of phytoplankton response to phosphorus deficiency are also summarized. Recent studies indicated phosphorus could be adsorbed onto phytoplankton cell surface. Distinguishing cell surface adsorbed phosphorus can help to assess the nutrient limitation on phytoplankton growth more accurately and to better understand phosphorus inventory and its marine biogeochemical cycle. Finally, challenges in further studies are suggested as follows: the mechanism on phytoplankton cell surface adsorbed phosphorus; the mechanism on utilization of different DOP pools by phytoplankton; the feedback and response of phytoplankton to phosphorus marine biogeochemical cycle.