Based on the fact that，in the actual project management，actions of the contractor and the client are interacted with each other and their profits are related closely，this paper investigates the project scheduling problem considering the interaction between the two parties of a contract． The authors identify the studied problem firstly，where the client exerts an effect on the contractor through the payment arrangement so as to obtain a desirable profit，while the contractor reacts to the client by adjusting activity schedule with the objective of maximizing his own profit．Then，taking the maximization of the project’s net present value as the objective，the authors construct a project scheduling optimization model which is composed of two submodels， namely，the contractor and the client submodel．For the strong NP-hardness of the problem，a special tabu search heuristic algorithm is developed． The algorithm is tested on a standard instance set generated randomly and the results show that the algorithm is an efficient algorithm for the problem．Ultimately，an example is utilized to illustrate the research and the following conclusions are drawn: With the postponement of the project deadline or the augment of the contractor’s profit baseline，the profit of the client tends to decrease while that of the contractor tends to increase．