Based on nutrients and hydrological data collected in the center of the Bohai Sea in July 2013, November 2013 and May 2014, nutrient spatial distributions and seasonal variations were examined in this study, and the nutrient limitation conditions for phytoplankton growth were also analyzed according to the minimum threshold of nutrients required by phytoplankton and their stoichiometric compositions. Results showed that nutrient concentrations and compositions varied significantly with a seasonal cycling. Nutrient concentrations were high in the autumn but relatively low in the summer and spring. In the summer, influenced by diluted water influx, seawater stratification was formed. Concentrations of dissolved inorganic nitrogen (DIN), reactive phosphate (PO₄^3--P) and reactive silicate (SiO₃^2--Si) were (10.33±7.75), (0.05±0.03) and (3.94±3.19) μmol/L, respectively. And DIN/P ratios were high and Si/DIN ratios were far below 1. In the surface and 10-m layers, stations with P limitation accounted for 93% of all stations, stations with Si limitation accounted for 40% and 20%, respectively, revealing serious limitation status of P and Si for phytoplankton growth. Due to the sediment resuspension and organic matter decomposition in the autumn, concentrations of DIN, PO₄^3--P and SiO₃^2--Si increased dramatically by 1.6, 10.8 and 4.3times, relative to the summer, to be (16.44±6.51), (0.54±0.20) and (16.94±6.37)μmol/L, respectively. The vertical variations of nutrients were small and only PO₄^3--P showed potential limitation to phytoplankton growth. In the spring, concentrations of DIN, PO₄^3--P and SiO₃^2--Si decreased by 45%, 89% and 85%, compared to those in the autumn, to be (9.04±8.06), (0.06±0.04) and (2.47±1.90)μmol/L, respectively, because of the decreasing of riverine outflow and increasing phytoplankton uptake. At some stations, concentrations of PO₄^3--P and SiO₃^2--Si were below the nutrient threshold of 0.03μmol/L and 2μmol/L for phytoplankton growth, respectively. In the surface and 10m layers, 70% and 65% of surveyed stations were in the status of P limitation, meanwhile 55% and 50% of stations were in the status of Si limitation, therefore, the primary production and diatom-dominant phytoplankton structure might be affected in the study area.