本文旨在考量決策者投資行為深受主觀的貨幣預期效用所影響，其投資效用滿足對數型效用函數。當市場規模處於高度不確定性下，專案價值依循幾何布朗運動，投資策略非僅限於預期貨幣價值，而考量決策者之預期貨幣效用高低為依據，應用實質選擇權法對投資策略進行分析，試圖探討最適進入及退出市場門檻值，並比較此等決策門檻值與風險修正後淨現值法所產生決策門權值之差異。經由數值分析結果得知，若決策者為風險規避者，其預期貨幣效用滿足對數型效用函數時，實質選擇權法之進入市場策略衡量較淨現值法較為保守，退出策略時則更為彈性。

This paper aims to assess the investment decision which is impacted by expected utility on money subjectively. The investment utility function of decision maker is assumed to follow the logarithmic utility form, and the strategic value is evaluated by not only the expected value of money but also the expected value of utility on money. Thereafter, applying real options to price the threshold for entry-exit investment strategy and the potential investment value will be calculated while the proposed model applies logarithmic utility and net present value method with risk adjusted, separately. As the results from numerical analysis know, the real option approach is more conservative than from net present value method in entering market, and is more flexible than from net present value method in exiting market.