Based on the data of nutrients, chlorophyll a and hydrological environment parameters collected in Bohai Bay during the early summer of 2016, we studied the distributions of nutrients and analyzed their possible limitation on the phytoplankton growth by analyzing both the minimum threshold and N:P:Si atomic ratios of nutrient required by phytoplankton cells. The results showed that concentrations and spatial distributions of nutrients were influenced by terrigenous input, cold water from central of Bohai Sea and phytoplankton uptake. Both dissolved inorganic nitrogen (DIN) and silicate (SiO₃^2--Si) concentrations decreased from nearshore to the offshore bay mouth, and the mean concentration of DIN was (7.67±6.48) μmol/L and SiO₃^2--Si was (5.44±3.01) μmol/L. In the surface of bay mouth, the concentration of DIN was (2.21±2.94) μmol/L in average, and 50% of samples was below the threshold, especially, 58.3% of them showed DIN limitation for phytoplankton growth. Comparatively, concentrations of activated phosphate (PO₄^3--P) were high in the nearshore and the bay mouth due to riverine input, and a zone with low concentration appeared in the middle probably caused by the phytoplankton uptake. The mean concentration of PO₄^3--P was (0.07±0.07) μmol/L in the whole study area. The concentrations of PO₄^3--P in the surface water were below the threshold of 0.03μmol/L at about 74.3% stations in the middle zone of study area, showing an obvious P limitation for phytoplankton cells. With the increasing disparity of riverine input between nitrogen and phosphorus, the P limitation for phytoplankton would be more serious in our study area.