Based on remote sensing images and geographic information system technology, the coastline and reclamation information of Fangcheng Bay in China and Haiphong Port in Vietnam from 1980s to 2010s were compared. The results showed that in the past 30 years or so, the coastline of the two places mainly migrated to the sea, of which the average end point rate of Fangcheng Bay was 6.49 m/a, and that of Haiphong Port was 6.21 m/a, showing a trend of rising first then falling and falling first then rising, respectively. In the 1980s and 1990s, the average end point rate of Fangcheng Bay was higher than that of Haiphong Port, while in the 2000s and 2010s, it was the opposite. In the past 30 years or so, the average new reclamation area of the two bays was 122.48 hm²/a and 164.24 hm²/a, respectively, and the reclamation intensity index of the two places showed a rising trend. In the 1980s and 1990s, the reclamation intensity index of Fangcheng Bay was smaller than that of Haiphong Port, while in the 2000s and 2010s, it was the opposite. From 1980s to 2010s, the reclamation area and the average spatial expansion rate per year increased first in Fangcheng Bay and then decreased, while Haiphong Port continued to fluctuate. Reclamation was the main factor for the change of the coastline of the two places, and port construction was the main driving force.