Esfandiar, the young and powerful Prince of Persia, was the true son of his domineering father; Goshtasp, his father, had hunger of power. He could not easily give the royal throne as fee to Esfandiar because of his self-sacrifice. He disappointed his son in achieving what he had promised. This article tries to analyze the psychological consequences of this failure in Esfandiar in an analytical manner. The following questions are also answered: How did failing to reach the royal throne affect the behavior of Esfandiar as one of the heroes of the Shahnameh? And how did he manage to soothe his mental and inner ailments. In the psychoanalytic school, the assumption of frustration-aggression has been proposed. And its aim is this: Whenever anyone fails to achieve a goal, the motivation for aggression increases. Aggression is defined as behavior that can lead to personal, spiritual, physical or property damage. And it happens when a barrier is created toward the presence of the desired object and the psychological pressure of his frustrations is gathered inside him. This is unconsciously shown as the expression of aggression in his manner. So, without being aware of his accumulated anger, by using the psychological defense mechanism of displacement, he vent his anger on Rustam, who was not his source of failure. Therefore, he could not be flexible with Rustam and his rational proposals to prevent a disaster.