To identify distribution and development of coast erosion in the Liaodong Peninsula, the development characterietics of erosion and siltation are studied based on the data from field investigation. Results show that coast erosion in the Liaodong Peninsula can be divided into five grades of serious erosion, intensive erosion, erosion, micro-erosion and stability. The sandy coast in Suizhong and Bayuquan area, rocky coast in Jinshitan area and silt-muddy coast in Zhuanghe area have been eroded seriously. Moreover, developmental characteristics and formation causes of coast erosion in typical coastal zone of Liaodong Peninsula are evaluated. The typical coastal zone is important to erosion control and management in a coastal zone. Recently, the decrease of river sediment into sea is the main reason for coastal erosion of Liaodong Peninsula, and sea level rise caused by climate warming plays a controlling role on coastal erosion. In addition, sand excavation and unreasonable coastal engineering have further intensified the degree of local coastal erosion.