China is actively building intelligent oceans to develop the marine economy and protect the ecological environment. Over the past 30 years, China has developed a large number of marine projects for economic development, such as sea reclamation, the establishment of water-passable or water-impassable jetties, dykes, and approach bridges. To reduce the impact on marine hydrodynamics and the ecological environment, China has banned most of its sea-enclosing activities, and water-passable structures are more and more developed and applied in practical projects in China. However, there are no clear judgment criteria for the definition of water-passable structures, and there is a lack of reference for the criteria in the management and development of water-passable structures. This has led to mismanagement, such as the fact that sea enclosures that have a subtle permeability but have a significant impact on the marine environment have been judged to be water-passable structures, which has harmed the marine ecosystem. At the same time, the foundation of the intelligent ocean includes comprehensive access to information on sea-related activities (ocean management, resource development, ecological civilization construction, etc.), and the lack of uniform determination standards makes the information on offshore structures mixed and makes it impossible to establish a standardized management system, which is not conducive to the further development of the intelligent ocean. To put forward the judgment criteria of water-passable structures, this paper establishes a conceptualized hydrodynamic model of linear shaped structures offshore China by analyzing actual data from a survey. According to the simulation results, in typical cases, based on the principle of ecological priority and strict control, this study suggests that linear shaped structures with a permeability greater than or equal to 70% should be recognized as water-passable linear shaped structures, and those with permeability less than 70% should be recognized as water-impassable linear shaped structures. The judgment criteria of water-passable linear shaped structures from the perspective of permeability can help the development and management of water-passable structures in Chinese coastal areas (e.g., sea area use demonstration) to be more accurately carried out, to protect the marine ecological environment and to realize sustainable development. At the same time, it provides a reference basis for China to further build a unified management method for marine structures and promotes the construction of the Chinese intelligent ocean.