Abstract: The collaboration of contractor and supplier in mega project has a significant help for the production schedule enhancement and quality improvement of key equipment and prefabrication resources. Therefore, the owner often takes a variety of incentives to encourage the collaboration between contractor and supplier such as the establishment of prizes, which the distribution mechanism of benefit will influence the collaboration performance. In order to promote the collaboration and enhance the performance, the collaboration of contractor and supplier in mega project is taken as the object of the research. Based on the differences of decision environment, decision order and decision purpose, two dynamic game models which are decentralized decision making model and centralized decision making model are designed. Given the difference between contractor and supplier, the model highlights the weight of contribution. Then the best profit distribution mechanism, the best effort and the best benefit are given. Also comparative analysis and numerical modeling are taken. The research shows that when contractor's effort and supplier's effort all have the impact on the output, the profit must be shared which can incent the enthusiasm of collaboration. The distribution coefficient is only affected by the weight of output contribution. The contractor's distribution coefficient is positively correlated to his own weight of output contribution, while is negatively correlated to the supplier's weight of output contribution. The best effort and best revenue are negatively correlated to the cost coefficient of either side. When the bilateral moral hazard exists, the contractor's benefit in decentralized decision making model is higher than its in centralized decision making model, so contractor prefer to choose decentralized model, while the supplier is inverse. It is also indicated that the benefit of the supply chain system is optimal in centralized decision making model. The research will have a great help for decision making and strategy selection of contractor and supplier in their collaboration.

Key words: collaboration, decision-making model, mega project, profit distribution