Abstract: The Bohai Sea is a key area in China in terms of socio-economic development. In this paper, we studied coastline changes, such as the changes in length and area in different periods for the past 30 years. The results of this study show that over the past 30 years, the coastline of the Bohai Sea was mainly moving towards offshore. The length of the coastline was increasing in general and the total length of the coastline increased from 2 258.81 km in 1960 to 3 437.59 km in 2016. Artificial coastline, in particular the embankment coastline, increases rapidly. The largest changes in the end rate of coastline are found in the period of 2006-2016. The Tianjin section and Shandong section of coastline are the ones which kept highest end point rates in the period of 1986-2016 in a trend of advancing, due to the increase in human activities. Owing to the coastal construction and land reclamation during the studked period, the utilization of coastline in each coast section of the Bohai Sea is also increased tocertain extent. The influence of human activities, in particular land reclamation, played critical rolesin the changes of coastline.