Abstract: Field survey was carried out at 14 sites along the Xiangxi Bay,which had been the former Xiangxi River prior to theconstruction of Three2Gorge Reservoir,during a spring phytoplankton bloom (2,Feb.228,Apr.,2005). The sampling sites distributed from the mouth of Xiangxi River (where adjacent to the Yangtze River) to the head of the Xiangxi Bay.And field surveywas performed every six days,and the water was sampled and preserved with pH <2 using H2SO4. The concentrations of nitrateand phosphate of the water sample were analyzed by the Segmented Flow Analyzers (Skalar,Netherlands) using the standardmethods. The results showed a legible representation for the spatial and temporal distribution of the nitrate and phosphate. In thespatial,the concentration of nitrate was high in the mouth of the Xiangxi River and low in the head water of the Xiangxi Bay.Andthe concentration of nitrate was decreased with the distance increased from the mouth of the Xiangxi River. The spatial pattern ofphosphate was reverse to the nitrate. The concentration of the phosphate was low in the mouth of the Xiangxi River and high in thehead water of the Xiangxi Bay. The concentration of the phosphate was increased with the distance increased fromthe mouth of theXiangxi River. The spatial distribution of nitrate and phosphate may indicated that nitrate diffusion from the Yangtze River andphosphate diffusion from the head water of the Xiangxi Bay were the main factor driving the spatial pattern of nitrate and phosphate in the Xiangxi Bay. In the temporal,the variation of the concentration of nitrate in the sites near the mouth of the XiangxiRiver was small,and the variation in the head water of Xiangxi Bay was large.With the distance from the mouth of Xiangxi Riverincreased,the variation of nitrate was increased.A large variation of the concentration of phosphate was found in the middle reachof Xiangxi Bay (S04-S08).