Organizations and companies are always looking for accurate, timely, and quality performance of their activities and projects, often through the proper management of different dimensions of activities and projects. The topic of motivation and reward of employees and managers in project activities is part of the human resource management discussed in this article. In the mathematical model of this paper, three bases are assigned to each individual reward in each project: project strategic importance, project performance evaluation, and individual role in the project. The model provided by these fundamentals and the limitations of organizational resources assigns each individual to each reward project. How to calculate reward in a way that takes into account financial constraints, first, encourages employees to define projects that are more in line with the goals and strategies of the organization, and second, encourages them to commit to the project's quantitative and qualitative requirements. At the end and via a case study, the model is implemented in Iran Argham and the results show the improvement of company projects' performance in terms of time, cost and quality of deliverables.