A long investment cycle and complex environmental changes bring lots of uncertainty to urban rail-transit (URT) project investment, and lead to many investment risks. However, investors' aggressive flexible management strategies may effectively avoid the risks and create greater investment benefits. In order to scientifically evaluate the potential benefits brought from flexible management, this paper systematically builds an analysis framework for investment benefits evaluation based on real options theory. Previous studies have still been confined to the single option benefits measurement and the evaluation methods assume that expected investment cost and income were constant. To fill the gap, this study takes account of the interaction effects of several real options and uses fuzzy theory to relax some parameter hypotheses, then establishes a multiple-fold compound real-option benefits evaluation model based on trapezoidal fuzzy numbers. Another contribution of this paper is that it provides a clear modeling approach for estimating the parameters of investment benefits volatility and discount rate by using historical open data in the financial market. A case study of the Changsha Metro Line 2 in China is discussed, and the empirical analysis shows that option benefits account for a large proportion of the entire investment returns. Moreover, the compound option benefits are about five times of the single option, so the implied option benefits, especially the compound option benefits, should not be ignored in the measurement of the URT project, and investors should be encouraged to actively implement flexible management strategies. Finally, this paper makes a sensitivity analysis of compound option benefits, and provides a basis for effectively reducing the government's subsidies and achieving profitability of URT project investment.