This paper deals with the distribution features of SO2-4，,ΣS(-II), S2- in seawater and sediment interstitial water, and diffusion flux of sulfur near the sediment-seawater interface in the Huanghe River Estuary's northern district. SO2-4，,ΣS(-II), and S2- concentrations in seawater are high inshore and low offshore, and the vertical changes are small, In sediment interstitial waters SO2-4 concentrations are low inshore and high offshore; in surface interstitial waterΣS(-II), and S2- concentrations are high inshore and low offshore; in 30-40cm layer of interstitial waters, ΣS(-II), and S2- are low inshore and high offshore and change strongly in vertical distribution. In general, SO2-4 tends to decrease, ΣS(-II), and S2- tend to increase in vertical profiles. SO2-4 diffusion near the sediment-seawater interface is from overlying water to sediment, and the diffusion flux is -1.614mmol/㎡.d inshore, but HS-and S2-. diffusions are from sediment (interstitial water) to overlying water, and the diffusion flux of HS- is 8.950 μmol/㎡.d offshore。