Abstract: The ratio between the value of marine industry and GDP was 9.3% for the gross output value, and was 4.0% for the added value in China in 2005. In this paper the gray correlation analysis was used for dissecting the dominant industries in marine industrial structure of the country in 2001-2005, which were coastal tourism, fishery, transportation and so on. The principal component analysis was applied for evaluating the positions of marine economic comprehensive strength of coastal provinces in the country, in which Shanghai, Tianjin, Guangdong located the first, the second and the third positions respectively in 2004. The regional position entropy analysis was used for determining the superior marine industries of coastal provinces, for example, the superior marine industries of Shanghai were transportation, coastal tourism and shipbuilding industry in 2004. On the basis of above-mentioned analyses the development tendencies of sea fisheries in China were looked forward to, in which the annual increasing rate will be zero for offshore fish catches, will be 3.7 percent for mariculture production, and will be 6.4 percent for oceangoing catches in 2005-2020.