本研究提出下述假說：文化是一國產業發展管理不可或缺之要素，並透過跨國七個案例作為證據，分析此假說之價值性或成立之可行性。研究發現波特鑽石理論之六大要素若能加入第七要素 - 文化，其完整性可能更好；因為七個案例均顯示文化是不可或缺的要素，且國家文化與產業特性(或文化)必須配合，一國之產業才具有國際競爭優勢。此外，本研究也發現波特鑽石理論中有些要素並非必要，且隨時代環境之變遷，部份要素的定義可從新界定。 This thesis presents the following hypothesis: Culture is an imperative element of national competitive advantage in an industry. It is designed to explore the value and probability of accepting the hypothesis by means of evidence from seven case studies around the world. This research finds that it would be a more effective model for analyzing the national competitive advantage in an industry if Porter’s Diamond were added seventh factor－culture. The main reason is that seven case studies all show culture is an indispensable factor and compatibility between national culture and industry culture is necessary. In addition, this study also finds that some of the factors in the Diamond Theory may not be further applicable or required. So with the change in time and environmental trend, some factors may need to be re-defined.