In project management, the main purpose of proposed methods is project scheduling which helps to management and planning. We can calculate a real average of project closure in dynamic PERT networks by identifying a lower limit. According to randomness, each distribution parameter varies itself and also it is proposed that activity durations are exponential distributions which have casual, unstable and independent variables. We used hypothetic kinetic programming, that project closure time would have a lower limit. Finally, delivery time would obtain optimal due date by minimizing the expected aggregate cost per project and also a linear function of its due-date.