Abstract PROMETHEE is an important method for multi-criteria decision-making. Inspired by ensemble methods, this paper proposes an ensemble PROMETHEE II model, in which multiple preference functions are used to reduce the risk of choosing a particularly preference function. One example of competitiveness evaluation of the ports of Circum-Bohai-Sea is included to illustrate the proposed method. The ranking results show that the whole evaluating procedure is simple and clear, and the model has taken full advantage of information contained in the original data and the subjective information of experts.