<p>In mega-infrastructure projects, with the development of industrialization in construction engineering, the construction of these projects has begun to shift toward the use of custom prefabricated parts. The famous Hong Kong–Zhuhai–Macao Bridge and the West Bay Bridge in Macao have adopted prefabricated construction methods to varying degrees. The large-scale and stringent technical quality requirements of mega-infrastructure projects pose significant challenges for resource supply. The quality of the prefabricated parts provided by suppliers plays a crucial role in ensuring the project's stability and safety. However, suppliers may engage in opportunistic behavior during the prefabricated product production stage, resulting in substandard prefabricated components that pose a threat to installation safety and project integrity. To prevent the behavior from causing engineering risks, owners need to establish incentive mechanisms. Based on the Kreps–Milgrom–Roberts–Wilson (KMRW) reputation model and the multitasking principal–agent model, this study analyzes the possibility of suppliers providing cooperative efforts and adopting opportunistic behaviors in a multistage game process, and establishes a dual-reputation incentive mechanism. By incorporating dual-reputation factors into its incentive mechanism design, this study is more suitable for engineering practice, offering owners an engineering-practicable framework to effectively align supplier efforts with project quality requirements.</p>