Selecting the statistical data of the eastern, southern and northern coastal areas of China from 2013 to 2020, the entropy weight method, the coupling coordination degree model and the gray prediction model are used, to explore the coupling and coordination relationship between regional scientific and technological innovation and digital economy in coastal areas. The research shows that the scientific and technological innovation capabilities of the three coastal areas in China are on the rise as a whole, and the northern coastal areas have a higher starting point, but the increase is not large. The development of the digital economy in the three regions has also generally shown a steady upward trend. The northern and southern coastal areas have experienced a slight decline in 2020. The degree of coupling and coordination between regional scientific and technological innovation and digital economy in the three regions has steadily increased. The northern coastal areas are in a good coordination state, and the eastern and southern coastal areas are in a high-quality coordination state. The northern coastal area has great development potential and will reach a state of high-quality coordination in the later stage.