Recently designated as a new special economic zone in China, Zhoushan Archipelago is going through a rapid land use change that is expected to have significant impacts on ecosystem services. However, there is no baseline of ecosystem service value (ESV) of the Zhoushan Archipelago up to date, making it impossible to assess any impacts of land use changes. In this study, we adopted the concept of "equivalent value per unit area of ecosystem services in China" and computed the ESV for 2006, 2012, and 2020 of a representative district, Dinghai, on the Zhoushan Archipelago. We then analyzed the spatial and temporal patterns of land use changes and their impacts on ESV. The results indicated that the ESV of Dinghai District declined by 59.3 M Chinese yuan ($9.5 M US dollars) from 2006 to 2012 and would further decrease by an additional 30.9 M yuan ($5 M US dollars) by 2020 according to its planned land uses. These declines in ESV were primarily due to increases in buildup areas and losses in wetland, farmland, and water areas. The results imply that more attention should be paid to controlling urban growth and protecting coastal wetlands in order to preserve valuable ecosystem services of the Archipelago.