The acceptance of the right project which leads to the realization of the set objectives is one of the most important issues in project-oriented companies. Therefore, corporate managers prefer to work on those projects which ensures the achievement of goals such as increasing financial profits or being the top brands in their rivals market. The present research aimed at introducing a systematic approach to the project acceptance modeling in order to ensure that effective decision-making can be seen and analysis them with appropriate model. This paper provides a system dynamics model of project accepting which examines the effective factors in decision-making process. This data used in the present research included number of staffs assigned to the projects as well as the identified of delay in project execution. The identified factors have been used to indicate the cause and effect relationships in graphs and calculating the related equations before being integrated into the model. Finally, sensitivity analysis was done by running model and validating it to determine suitable strategies which improve the decision-making of managers when dealing with the process of accepting or rejecting available market’s projects. Therefore, the results can be used in decision–making process.