Huge amounts of energy and resources will be consumed, and a large quantity of environmental pollutants will be produced during the construction process of large-scale hydropower projects. As a core link of green supply chain in hydropower projects, green construction is particularly critical. To objectively evaluate the green construction level of large-scale hydropower projects, an evaluation indicator system was constructed in the study. The evaluation system consisted of 30 quantitative indicators and 7 qualitative indicators from the perspectives of environmental protection, resource saving and comprehensive management on the basis of the construction characteristics of large-scale hydropower projects. The quantitative and qualitative evaluation standards were proposed by combining with relevant laws and regulations, specifications and standards, and the environmental management maturity model. Furthermore, taking the second quarter of 2018 in Wudongde Hydropower Station on the Jinsha River, China, as an example, green construction level was assessed by the analytic hierarchy process fuzzy comprehensive evaluation (AHP-FCE) method. The calculation results indicated that the evaluation value of green construction in Wudongde Hydropower Station was 3.697, at “Good” level. The evaluation values of environmental protection, resource saving, and comprehensive management were 3.681, 3.473, and 3.965, respectively, within the range of 3 to 4, so they were all evaluated to be “Good”. To further improve the green construction level, it was necessary to supervise some aspects of construction process, i.e., treatment of waste slag in construction, economical and intensive utilization of land, publicity and training, soil erosion control, and saving water resources. In particular, management of soil erosion control should be strengthened. The proposed green construction evaluation system is relatively reliable and practical for professionals in the green hydropower industry, and can provide a reference for other large-scale hydropower projects.