Dahuangpu Wetland is the nature reserve of Tianjin City. The nitrogen, phosphorus and heavy metals contents and releasing of sediment in Dahuangpu Natural Wetland were studied in this paper. The results indicated that the contents of TN and TP in the wetland sediment were lower than the Lowest Effect Level (LEL) in the Guidelines for the Protection and Management of Aquatic Sediment Quality in Ontario, Canada (PSQGs), which means the sediment had no great eco-toxicity on dwelling organisms. Meanwhile the contents of heavy metals, namely Cr, As, Zn, Ni, Pb, Cu, Hg and Cd, in Dahuangpu Wetland sediment were lower than LEL of PSQGs and lower than primary standard of Environmental quality standard for soils (GB15618-1995). Moreover the influence of nitrogen, phosphorus and heavy metals releasing on wetland water qualities were trivial.