Research is conducted on the following questions: 1) the seasonal and spacial changes of Fe2+ concentration in overlying water and interstitial water; 2) the profiles of Fe3+ and Fe2+and total Mn in solid phase of sediment; and 3) the estimation and comparison of Fe and Mn diffusion and deposition fluxes.The complex relation among the early diagenesis of iron, the grain size composition in solid phase of sediment and the factors of pH and Eh as well as dissolved oxygen are reflected by seasonal and space relation of Fe2+ change.The geochemical activity and role of iron and manganese during diagenetic processes is discussed and estimated by calculating and comparing deposition and diffusion fluxes of both the elements. Research is conducted on the following questions: 1) the seasonal and spacial changes of Fe2 + concentration in overlying water and interstitial water; 2) the profiles of Fe3 + and Fe2 + and total Mn in solid phase of sediment; and 3) the estimation and comparison of Fe and Mn diffusion and deposition fluxes. The complex relation among the early diagenesis of iron, the grain size composition in solid phase of sediment and the factors of pH and Eh as well as dissolved oxygen are reflected by seasonal and space relation of Fe2 + change The geochemical activity and role of iron and manganese during diagenetic processes is discussed and estimated by calculating and comparing deposition and diffusion fluxes of both the elements.