Yingkou was formerly known as Newchwang, is one of the Treaty Ports opened under the Treaties of Tianjin of 1858. In fact the town of Newchwang was about thirty miles upstream of Liao He and the Treaty Port was actually at the Port of Newchwang. After the treaties is signed, the British found that the river near Newchwang was too shallow. Instead, the treaty port was moved to the area near river mouth where today's Yingkou locates.

In late 2005, the Party Secretary of the Liaoning Provincial Committee of the Communist Party of China, Li Keqiang, initiated the "Five Points, One Line" strategy to develop the entire Liaoning coastline, and in particular focusing on the "five points" of the Changxing Island Harbor Industrial Zone in Dalian; Yingkou Coastal Industrial Base; Liaoxi Jinzhou Bay Coastal Economic Zone; Dandong, and the Zhuanghe Huayuankou Industrial Zone.

As a result, Yingkou city is currently undergoing substantial expansion. From its current urban area of 54 square kilometres, Phase One of the Coastal Base project is under way and is adding a further 44 square kilometers of industrial and urban areas to Yingkou. Phase Two (planned to start in 2010) will add a further massive 157 square kilometres.

The land being used is largely marshland and reclaimed from the sea: in particular, it is largely unoccupied. As a result, the social and fiscal costs of development are less than are usual for Chinese urban and industrial development.

The Yingkou port area is also being very substantially increased in size, in the Bayuquan and Xianren harbours.