Recently, there has been growing concerns about environmental issues related to urbanization in China. The intense natural resources utilization and increasing population has brought great pressure,especially in coastal areas, consequently affecting the sustainable development of coastal cities. In 2002,Environmental Impact Assessment Act (EIA Act) was enacted in China. Environmental impact assessment targeted at planning, one level of strategic environmental assessment (SEA), thus became a legislative requirement.This paper considers SEA to be one of the important approaches not only to control coastal pollution, but also to conserve coastal ecosystems and finally to achieve sustainable development during urbanization, thus it will be a set an example for other areas of China. The experience of SEA in Xiamen, a coastal city in southeast China, illustrates the potentials of SEA. This paper first briefly introduces the concept and potentials of SEA,then compares two SEA cases and a project EIA case in Xiamen, and finally identifies the key characteristics of SEA.