本文應用模糊理論於資本預算並結合機率方法以發展評估投資計劃之模糊淨現值運算式。以模糊數估計現金流量可捕捉估計之模糊特性，且對經濟展望之機率預測可描述結果之隨機性。本研究使用模糊數之α-截集與信賴區間，定義出模糊淨現值、其期望值與標準差、並導出歸屬函數。然後提出模糊績效指數，即模糊淨現值之期望值除以其標準差，作為決策指標。經排序程序後，績效指數愈高者為愈佳選擇本研究同時對過去文獻較少討論之互斥計劃之不等存續與不等資金成本情況，進行模糊等值年金與模糊永續化等值年金之估計，暨其模糊績效指標之排序。所提出之歸屬函數之逐步運算公式或能促際執行之便利。最後，以一個數值範例來展示所提運算式之可行性。

　　　　　This work applies fuzzy theory to capital budgeting and combines with a probability method in developing the fuzzy net present value algorithms for evaluating the investment projects. The estimation of cash flows in fuzzy numbers catches the vague characteristics of estimation, and the forecast of probabilities of economic prospects describes the randomness of outcomes. Using α-cuts and the interval of confidence of fuzzy numbers, this study defines the fuzzy net present value (FNPV), expected FNPV, and deviation, and derives their membership functions. The fuzzy performance index (FPI), the fuzzy expected value to standard deviation, is then proposed to be the decision indicator. After a ranking procedure, the higher-FPI project is a better choice. The situations of unequal durations and unequal costs of capital for mutually exclusive projects, which are seldom discussed in previous studies, are considered by estimating the fuzzy equivalent annuity (FEA) and fuzzy equivalent annuity to infinity (FEAI). The ranking of their FPIs is also derived. The proposed step-by-step operational algorithms of the membership functions hopefully conduce to more convenient practical implementation. Finally, a numerical example demonstrates the feasibility of the proposed algorithms.