China seas and their adjacent areas are the key areas for establishing the "21st Century Maritime Silk Road" and building a community of marine destiny and promoting sustainable development. They also constitute one of the most typical and representative research areas in earth science. The 1:1 million regional geological survey of China seas is a national basic public welfare marine geological work guided by national demand. Through the continuous investigation of nearly 20 years, China Geological Survey has realized the comprehensive coverage of 1:1 million regional geological survey of China seas and systematically obtained the basic data of marine geology and geophysics. Based on these numerous data, the comprehensive achievements of“one series of maps, one data set, one research report”have been recently raised to a new level. These results have vigorously improved the overall level of the marine geological work of China and filled in the blank of small-scale marine geological survey of China. The work has preliminarily found out the geological structure situation and the potential of resources and environment in China seas and also provided detailed and reliable geological data to serve the needs of national economy and social development.