Hakīm Abu'l-Qāsim Ferdowsī `s Shahnameh (epic of the kings) is the most punctilious and artistic versified work of the world and Iran literature. Multiplicity of characters in this work and their acts and interactions indicate that its creator was fully aware of many personal and psychological points and ideas, and paid the necessary attention as soon as creating the characters. Rostam , the national hero of Iran, is the most effective character playing numerous roles for Iran and is the main Shahnameh`s paladin of denouement. This study was aimed at evaluating the emotional aspect of Rostam-e Pil tan (strong), because, in the tragedy of Rostam and Sohrab and the story of Siavash, he shows the most trivial emotions and, since Ferdowsī is worry about the destiny and psychological conditions of Shahnameh characters, giving the rearing of Siavash to Rostam and replacing his emotion toward Siavash, desires his spiritual and psychological consolation. This indicates the deep attention and cognition of the poet to psychological issues and human personality. The role of Rostam in the story of Siavash matches the theory of defense mechanism and coping with psychological pressure. Having no opportunity to be the mentor of his own son (Sohrab), Rostam wants to satisfy his personal and psychological lacks when he meets Siavash. He sees Sohrab in the mirror of Siavash and, with the defense mechanism, leads his unsatisfied motifs to a place where his psychological stresses are reduced, and his self-respect is preserved.