Halomonas sp.YSR-3 was isolated from the Yellow Sea and identified as a polyphosphate-accumulating bacterium and the characteristics of its intracellular polyphosphate (polyP) granules and phosphorus absorption were studied.Most YSR-3 cells stored one or two polyP granules in regular appearance and high-density.The diameter of the granules was about 400 nm measuring by a transmission electron microscope (TEM).After stained with 4,6-diamidino-2-phenylindole (DAPI) and visualized by a fluorescence microscope,the cells ted blue and the granules were bright yellow.The composition of granules includes P (major ingredient),Mg,S,K,and Ca as detected by an energy dispersive X-ray spectrometer (EDS).When inorganic phosphorus (po34-) and ferric ion (Fe3+) were added into media,the biomass increased and the cells formed intracellular polyP granules owing to the phosphorus assimilation from media.The YSR-3 obtained higher biomass by adding 0.02 g/L FePO4 than 0.005 g/L and 0.01 g/L FePO4;however,the phosphorus absorption was higher with 0.01 g/L FePO4 than 0.005 g/L and 0.02 g/L FePO4.The optical density at wavelength 480 nm (OD480nm) was 0.79 and 100％ cells could form intracellular polyP granules.These results show that strain YSR-3 is able to acquire higher biomass and absorb more inorganic phosphorus when 0.01 g/L FePO4 is added.The characteristics of absorbing and storing phosphorus as intracellular inorganic polyP granules have a potential for application in high-efficiency phosphorus removal in wastewater treatment.