湿地资源保护是全球生态保护的核心问题之一。在分析湿地资源保护的经济属性的基础上,以北京市野鸭湖湿地为案例,运用经济学的理论和方法以及清晰的图表重点分析了野鸭湖湿地资源保护过程中的外部性以及资源利用中成本与收益两个问题。研究结果表明:(1)从正外部性分析,个人收益小于社会收益,个人保护的湿地资源小于社会最优量,会造成湿地资源保护的不足;从负外部性分析,个人成本小于社会成本,个人对湿地资源的利用水平大于社会最优利用水平,造成湿地资源的过度利用;(2)根据湿地资源利用的成本收益分析结果,"搭便车"行为会造成湿地资源的退化甚至恶化;(3)明晰产权有利于湿地资源配置效率的提高。研究结果可以为中国湿地保护过程中出现的资源利用矛盾提供有益的借鉴,特别是为保护北京野鸭湖湿地提供理论支撑和政策建议。;A wetland ecosystem is one of the most important ecosystems on earth. It plays important roles in ecological balances and provides human beings with products such as food, water and entertainment. Therefore, wetland resource conservation is one of the key issues in global ecological environment protection. Based on the analysis of economic attributes of wetland resource conservation and the theories of property rights, public goods and externality, this research, taking the Beijing Wild Duck Lake (BWDL) wetland as an example, emphatically analyzed (1) the externality in the processes of BWDL resource protection and (2) the costs and the profits in the BWDL resource utilization. The results show: (1) Individual profits may not be compensated due to positive externality, which leads to the deficiency of resources during the wetland protection. We hold that a reasonable compensation mechanism should be built in order to compensate the people who participate in the protection of wetlands. Only when their individual profits were safeguarded then can the social optimal point be achieved. In addition, people who destroy wetland resources may not be punished due to negative externality. If there is no valid constraint mechanism for these behaviors of destroying wetland resources, deterioration of wetland resources cannot be avoided. Hence, in the view of externality theory, the primary reason caused the wetland deterioration is the lack of compensation and constraint mechanism of positive and negative externality. (2) Free riding will lead to the deterioration of wetland resources. Taking cage fish culture in the BWDL as an example, we analyzed the negative effect from free riding. Results show that free riding existed in the utilization of wetland resources, resulting in the excessive use of wetland resources. Once the carrying capacity of local wetland ecosystems was broken, wetland resources will deteriorate further. Hence, one of the most challenges facing by wetland resources protection is how to coordinate the contradiction between cost and benefit during the protection and utilization of wetland resources. (3) A clear property rights is good for wetland resources protection. Free riding and externality are, fundamentally, results of unclear property rights of wetland resources. In China, most of natural resources with characteristics of public goods belong to two types: state or collective ownership. The allocation efficient of wetland resources will be low under the condition of unclear property rights. Individual person who protect wetland resources cannot get expect revenue. Converting the operation right and revenue right to individual may be a good way to solve the above problems. Individual is response for cost and benefit during the utilization of wetland resources. The allocation efficient will be improved and market failure can thus be avoided. Thereafter, administers of wetlands should define behaviors and reasonability of damage behaviors of wetland resources. Meanwhile, they should also make clear about the right and responsibility of wetland resource users. These research results would provide references for the problems in wetland protection processes in our country. In particular, it can provide scientific basis and policy options in the BWDL wetland conservation.