This paper investigates available offshore wind energy resources in China's exclusive economic zone (EEZ) with the aid of a Geographical Information System (GIS), which allows the influence of technical, spatial and economic constraints on offshore wind resources being reflected in a continuous space. Geospatial supply curves and spatial distribution of levelised production cost (LPC) are developed, which provide information on the available potential of offshore wind energy at or below a given cost, and its corresponding geographical locations. The GIS-based models also reflect the impacts of each spatial constraint as well as various scenarios of spatial constraints on marginal production costs of offshore wind energy. Furthermore, the impacts of differing Feed-in-tariff (FIT) standards on the economic potential are calculated. It confirms that economic potential of offshore wind energy can contribute Corresponding author. Tel: +45 99403658 Fax: +45 98153788 E-mail address: lixuan@plan.aau.dk 2 to 42%, 30% and 29% of the coastal regions' total electricity demands in 2010, 2020 and 2030. The shallow waters along the coasts of Fujian, Zhejiang, Shanghai, Jiangsu and northern Guangdong are identified as suitable areas for developing offshore wind energy in terms of wind resources and economic costs. However, the influence of tropical cyclone risks on these regions and detailed assessments at regional or local scale are worth of further discussions. Nevertheless, the models and results provide a foundation for a more comprehensive regional framework that would address additional infrastructure, planning and policy issues.