Abstract: Based on the economic and environmental data from 2005 to 2015 of the seven coastal cities in the urban agglomeration of Beibu Gulf, the spatio-temporal characteristics of economic development and marine environment were analyzed and evaluated using environmental kuznets curve (EKC) and coordination coefficient, and the coupling characteristics of the marine environment and economic development were revealed.The result shows that:1) from 2005 to 2015, the economies in the major coastal cities of Beibu Gulf increased continuously, while the marine environment status showing a trend of "deterioration-amelioration-deterioration" generally.2) The relationship between marine environment and economic development in urban agglomeration of Beibu Gulf shows a positive "N" type in general.3) The coordination coefficient shows an uncoordinated result between marine environment and economic development in the urban agglomeration of Beibu Gulf and its seven cities except for Maoming City.Both the results of EKC and coordination coefficient analysis indicated the relationship between marine environment and economic development in Beibu Gulf urban agglomeration were uncoordinated.It is important to implement related policies for environmental protection under the carrying capacity of resources and environment in this area to realize the coordination and sustainable development of economic and marine environment.