現今的社會，由於企業經營環境的高度全球化，及資訊科技進化的速度愈來愈快，企業所面臨的挑戰是日漸提升的，也因而對資訊科技/資訊系統的仰賴程度大幅提高。更甚者，企業不僅僅是運用所謂的資訊科技/資訊系統來應付大環境的挑戰，同時也希望能運用資訊科技/資訊系統來提高自身的競爭優勢。就在這樣的背景下，對於企業來說，如何去定義一項IT/IS 的真正價值，及如何運用有限的資源並投資在正確的 IT/IS 上成了一個很重要的議題。為了滿足企業對於這樣的需求，本研究旨在運用 IT 投資組合理論，彙整過去學者及研究的結果，並予之修改，提出一套藉由三項衡量指標： IT alignment, Business Value, 及 E-readiness 來決策 IT/IS 投資優先順序的方法論。最後，我們將我們提出的方法論實際導入並運用在一個挑選的個案中，藉此來驗證本方法論的實用性及可行性。我們相信本研究的結果可以供未來的企業在評估IT/IS 投資計畫時使用，同時也可幫助後續欲研究 IT 投資組合的學者，在我們所提出的架構上繼續建構。 / Nowadays, as firms operate in a much more competitive environment due to the rapid speed of globalization and evolving technologies, firms rely on IT/IS much heavier than before. They use IT not just to cope with the environment, but also to gain competitive advantages. Therefore, it is important for firms to justify the real value of an IT/IS and to invest on the right while also critical IT/IS with limited resources. To fulfill this need, this research aims at developing an IT portfolio method to evaluate and determine the priorities of each IT/IS investments based on three criteria: IT alignment, business value, and e-readiness. A case study was applied to verify the reliability and feasibility of our proposed framework in real business practices. We believe the final findings are helpful to (1) practitioners who can use this framework to justify their IT investments; and (2) researchers who can build upon this model to further examine the application of IT portfolio methods.