Ports competitiveness derives from the operations of container carriers' ports-selection and routes-deployment; and be caused by many influential factors. The purpose of this study is to explore the influence of cargo-source impacts on port competitiveness. Firstly, the port traffics were predicted and formed the factor of cargo-source that be represented by the trends of increasing rates of traffics among those major ports across Taiwan-strait, and then the relatively port competitiveness have been evaluated using the different influential factors. Finally, the significance of factors has been analyzed. The methodology is Grey Theory due to the restricted information of mainland China. Results indicate that cargo-source is the most influential factor, and the infrastructures of ports are the worst significance for port competitiveness.