Abstract: Effective delination of ecological compensation areas and accurate calculation of compensation standards are central to ecological compensation research, and playing a crucial role in fostering regional coordinated development. Hainan Island's counties and cities were used as cases for this study. The output and input areas of ecosystem services were identified based on the supply-demand ratio of ecosystem services. By applying ecosystem service flows to determine the scope and intensity of these flows, we established an ecological compensation model that incorporates factors such as socio-economic development levels and residents' willingness to pay. The ecological compensation amounts for each county and city of Hainan Island were then determined. The results show that: (1) There exists a marked spatial variation in the supply and demand of ecosystem services across Hainan Island, with high supply and low demand in central mountainous areas, contrasting with low supply and high demand in coastal plains. Central and eastern regions, notably Qiongzhong, Baisha, and Wanning counties, contributed over 70% of the island's ecosystem service flows; (2) Between 2000 and 2022, the ratio of ecological compensation recipients to payers among the counties and cities in Hainan Island changed from 10∶8 to 9∶9, indicating a potential imbalance in ecosystem services supply and demand; (3) This study provides an accurate calculation of ecological compensation amounts and analyzes the feasibility of implementation, offering valuable insights to support ecological compensation policy development and promote sustainable development on Hainan Island.