This paper attempts to study the marine economy index system, and build the marine economic competitiveness index system of the areas along the South China Sea, with basic conditions, developmental environments, and performances included. Using the factor analysis method to conducting the empirical analysis, this paper gets the scores and the rankings of the five countries and Chinas three provinces of the arrears along the South China Sea, who need to optimize the marine industry structure, foster the infrastructure construction, and enhance the scientific and technological innovation, so as to achieve the goal of mutually building the green maritime silk road.