Abstract: In the context of the “maritime power” and the Belt and Road Initiative strategies, it is an important principle for the development and protection of coastal zones to adhere to the land-sea coordination.The big data information service platform of coastal geology under the overall planning of land and sea is an important technical support platform for the coordinated development of land and sea.To realize the efficient sharing, management and application of the geological achievements of the coastal zone, the big data information service platform of the coastal zone is built by using Internet +, big data and other technologies.According to the overall idea of land and sea coordination, the platform has established a land-sea integrated data model, realized the unified planning, comprehensive management and resource sharing of coastal zone data, and developed the demonstration application subsystems of coastal zone geological environment visualization, monitoring and early warning analysis, etc.The establishment of the platform plays a very important role in promoting the coordinated development of the society and economy in China’s coastal zone, providing strong support for the diversified subjects including the government, enterprises, social organizations and the public to conduct scientific research, decision-making and management, and providing a strong guarantee for the protection and management of the fragile ecosystem in the coastal zone.