Abstract: The paper analyzes the regional change rule and trend in the northern Liaodong Bay from the two aspects of length and curvature with RS technology. Using multi-source RS data such as MSS/TM/ETM+ series data of US Landsat, French SPOT/4-5 series data and China Resources Satellite ZY-1 02C data, combining with the methods of artificial visual interpretation and computer automatic information extraction, the coastal changes in northern Liaodong Bay during 1973-2012 are monitored. The study shows that the length and curvature of coastline in northern Liaodong Bay are both increasing, especially after 1997 when they increase rapidly. The middle section of the coastline has the fastest increasing speed, followed by the west section and the east section. The main driving force for the change is human factors.