Abstract: To study the environmental changes and evolution rule of coastal zones in Dalian City in the last 40 years, the paper uses GIS technology to extract and analyze the coastline information during 1984-2018 based on the historical images from Google Earth. The results show that the coastline has grown in three stages: low-high-low, separated by the years of 2004 and 2014. The growth rate of sea reclamation is highly correlated to the GDP growth curve. Spatially, the coastline changes are mainly distributed in the bay and estuary areas, with the main types of land reclamation and sea mariculture. The land reclamation area is mainly concentrated in the central and southern coast of municipal district and Changxing Island Development Zone, while the sea reclamation area is scattered in Wafangdian, Pulandian and Zhuanghe areas in the north and east.