Abstract: Evolutionary history of river mouth bars is of significance to environmental protection and resource development and management in estuaries. The topography of the Liaohe Estuary is complicated by shallow shoals. In this research, RS and GIS technology are adopted to reveal the evolutionary characteristics of river mouth bars. Discussion is also devoted to the driving force of the evolution. Research results show that the outer edges of the sand barriers in the Liaohe Estuary have been under the erosion recently and the shoal line retreated obviously owing to the decrease in sediment supply from upstream. Instead, the eastern edge of the Geligangzi Shoal and West Shoal are under siltation and the shoal line have moved eastward obviously, due to sediment supply from the outer edge of river mouth bars in addition to the sediment coming from the erosion of river shoal and river bed upstream. The central shoals of the main channel of the Liaohe River have continuously remained under deposition and expansion downstream.