As the important resource and sink of biogenic element nitrogen, marine sediments have significant effect on nitrogen biogeochemical cycling. It is the key of this research to make clear nitrogen forms in sediments. Nitrogen biogeochemical cycling in marine sediments is a complex process. This research is focused on nitrogen early diagenesis, counter-eutrophication, nitrogen cycling (including mineralization, nitrification and denitrification), and nitrogen flux at the sediment-water interface. Various theory models and analysis methods have been built up. By now, systematic knowledge of nitrogen cycling has been obtained. Therefore, little was known about the distribution and forms of nitrogen, the relationship between nitrogen and other nutrients cycling, the effect of strong metals in nitrogen cycling. especially idiographic forms of nitrogen in different grain-size sediments in various sea areas. To research on the distribution and forms of nitrogen in sediments is the key for learning how nitrogen forms and transports in sediments, utilization and burying degree of nitrogen, the effect of nitrogen in the biological chain, and the relationship between nitrogen and marine biological activities. The effect of nitrogen on marine ecological evolvement and marine biogeochemical cycling must be deeply studied. The ocean is the last region rich in resources that has not been completely exploited. How to exploit it properly is an important problem.