本文試圖利用模糊數學建立一適合國際企業公司從事進入國際市場時，選擇進入策略的可行模式。本模式係利用模糊集合理論與層級結構分析加以構建，提出國際市場進場策略選擇的一套演算法則，群體決策者藉由語言變數與模糊數對評估準則的相對重要性，與在各準則下，各替代策略之適合程度評等後，加以整合，得到各替代策略的綜合評價，稱為模糊適合指數。 文中亦提出如何由群體決策者之評分資料裡，直接導出群體之樂觀指數，而不是在資料輸出階段另行決定該樂觀指數，並利用所提方法對各替代方案之綜合評價進行排序，以選擇最適之市場進入策略。

This paper discusses the potential application of fuzzy set theory to foreign market entry model choice in the area of international business. An algorithm for foreign market entry mode selection is proposed. The algorithm is based on the concepts of fuzzy set theory and the hierarchical structure analysis. The linguistic variables and fuzzy numbers are used to aggregate the group decision makers’ subjective assessment about criteria weightings and appropriateness of alternative entry modes versus selection criteria to obtain the final scores called fuzzy appropriateness indices. We also propose a revised method for ranking fuzzy numbers with index of optimism which was proposed by Kim and Park. Our revised method is based on the stage of data input for computing the total index of optimism in militiaperson decision marking problem, instead of giving the index of optimism independently by a decision marker on the stage of information output. This new look at the index of optimism reflects the polled risk-bearing attitude of multi-judge. The index of optimism is determined by the evaluation data conveyed by the decision markers at the beginning of data input stage. Finally, we use our revised method to rank the fuzzy appropriateness indices for choosing the best foreign market entry mode.