Keywords: 
• engineering general contract /
• union /
• optimal benefit /
• fairness concerns /
• profit distribution

Abstract: When designing enterprises and construction enterprises are united to carry out a general contracting project, profit distribution is the key to the optimization of the project, which determines whether the advantages of general contracting can be given full play. However, profit distribution is not only affected by subjects' rational behavior, but also affected by the behavior of subjects' fairness concerns. From the perspective of behavioral science, based on game theory, the revenue model, fairness concern model and profit distribution model of the optimal benefit of general contracting projects were constructed in this paper. Then, three scenarios were set:either the designing enterprise or the construction enterprise has fairness concerns, and both sides have fairness concerns. Four indices-the feasible region of profit distribution, average profit, expected profit, and maximum profit-were selected to analyze the impact of subjects' fairness concerns on a project's optimal benefits and benefit distribution through simulation. The research results showed that appropriate fairness concerns of the subjects were beneficial to the promotion of their own benefits. However, when they paid too much attention to fairness concerns, it would lead to a drastic reduction in the viable region of the project's optimal benefit allocation; at the same time, the likelihood of project optimization and the expected return of project optimization would decline.