Ecosystem services were defined as the conditions and processes through which natural ecosystems, and the species that make them up, sustain and fulfill human life. They include provisioning, regulating, cultural, and supporting services. These form the basis on which regional environmental reserves and development are assessed and for the valuation of ecosystem services. In this paper Hainan Island is used as an example to explore methods of regulating services based on the structure and processes of a natural ecosystem. Ecosystems were classified into 13 types： valley rain forest, mountainous rain forest, tropical monsoon forest, mountainous coppice forest, mountainous evergreen forest, tropical coniferous forest, shrubs, plantation, timber forest, windbreak forest, mangrove, savanna, and crop land. Regulating services and their economic values for Hainan Island ecosystems were assessed and evaluated in terms of water-holding, soil conservancy, nutrient cycle, C fixation and windbreak functions. The economic value of the regulating services in 2002 were estimated at 2035.88×10^8 to 2153.39×10^8 Chinese Yuan （CNY）, which was eight times the value of provisioning services （wood and agricultural products）, estimated at just 254.06×10^8 CNY. Our analyses imply that ecosystem regulating services play a very important role in the sustainable development of Hainan Island＇s society and economy.
