Abstract: Ecosystem services and preservation costs of the coastal wetland ecosystem of Yancheng National Nature Reserve were analyzed. Various methods,i.e. market method, shadow-engineering method and expert evaluation method were used to valuate the ecosystem services of the coastal wetland. It was found that in 2010 the total cost of preserving the wetland ecosystem was 8.18×10⁹ RMB, of which 1.95×10⁷ RMB was management cost and 8.16×10⁹ RMB opportunity cost, while the benefits of the reserve totaled 1.83×10¹⁰ RMB. Results of the calculation show that the benefits the Yancheng National Nature Reserve generated far outweighed its costs, indicating that the existence of the Yancheng National Nature Reserve has a certain yield advantage in economics. Accordingly, the established Yancheng coastal wetland nature reserve has generated great ecological benefits, of which the advantage embody mostly long-term comprehensive benefits and could hardly not be encashed directly in money. Therefore, the construction and management of nature reserves should have an overall and long-term concept, which will not allow any sacrifice of the nature reserves for short-term or local interests. Only by then can we truly realize perpetual conservation and sustainable utilization of the nature reserves.