Abstract: Improving the economic efficiency of marine space resource utilization is an important measure for building marine power. This paper proposed a marine industry classification system, then constructed some mathematical models for study on the relationship between sea structure and economic value of marine industry, such as the industrial sea structure diversification index, economic output value and economic efficiency, and analyzes the relationship between the spatial resource use structure and economic efficiency. The conclusions were as follows: (1) The marine industry classification system had an important practical significance for other related research; (2) China's marine industry sea uses were mainly in traditional marine industries, such as fishery, transportation, engineering and construction, which distributed centrally in space; (3) The sea structure diversification index of China's marine industry was generally low, and the inter-provincial difference of ocean space resource use economic output value was obvious; (4) The economic efficiency of marine space resource use was basically positively correlated with the diversification index.