A costal improvement project is designed for preventing disasters on the coast, improving costal environment, and promoting costal functions, so it is different from the one for developing coasts. However, the costal improvement project also affects the surrounding environment and it may damage the costal environment in some cases. In line with this, this study was carried out to provide the guideline to the review on environmental conditions, which should be performed in the stage of establishing the plan for a costal improvement project, so that the influence affecting marine environment can be reduced and more efficient coastal project can be planned. The costal improvement project is different in the degree of affecting the costal environment according to kinds, scales, and regions. Accordingly, in this study the state of the coastal improvement project and involved problems were analyzed. The prior environmental review system was divided into a seawall-installation project, a marine construction such as the installation of submerged breakwater and jetties, and a project for creating water-friendly coast including a park without marine landfill. The main items for reviewing these specific projects were presented.