This paper presents the results of studies on the determination of the contents of different states of nitrogen in the Haihe River estuary area in the Bohai Bay. Distributional patterns and the process of migration of different states of nitrogen are discussed. It is found that in the Yongdingxing River, organic N is fully resolved, oxidized, and converted into inorganic N (TON →NH4-N →NO2-N→NO3-N), while in the southern sewage discharge river, it is not so. The higher contents of inorganic nitrogen are found only in the nearshore areas. Different states of nitrogen show the same positive correlation with CB and other factors. In the Yongdingxing River, bacteria play a main role in the conversion of organic nitrogen. Due to the influence of sewage discharge, the NO3-N/PO4-P ratio in the nearshore estuary area is 34, in the offshore area, 5 and 6.