On the basis of the theory of learning curve and the theory of forgetting curve, through the activity-on-arrow network, combined with the learn forget curve model of learning and forgetting effect, it can be concluded that the learning and forgetting behavior of employees cause changes both in schedule and critical path. The learning effect and the forgetting effect of employees will shorten the time limit, and change the critical path, compared with the case of not considering the learning and forgotten effect, and different learning ratios will have different effects.