Social psychology examines the social behavior of individuals against individuals and groups. Social psychology are discussed issues such as social relationships, conflict, and negotiation. The study and analysis of the story of Lohrasb and Goshtasb in Ferdowsi's Shahnam and the story of Achilles and Agamemnon in Iliad Homer provide a better understanding of these two stories in terms of social psychology. We have tried to compare the two stories descriptive analysis method, with a focus on behavior of Achilles and Goshtasb in coping with Agamemnon and Lohrasb, and study the causes of hostility, the similar behaviors and the consequences of hostility. Finally, we achieved the responses: Causes of enemity have been egoism of conflict sides, breaking pride of Achilles and Goshtasb and ignoring their needs in both stories. Goshtasb and Achilles have frustration for their opposite disrespect. They have tried to compensate their frustration by aggression, adaptive behavior, proving of themselves and negotiation leave. Enemy outcomes have been also very bad for Goshtasb and Achilles. So that Goshtasb accepted commander of the Roman army- enemy of Iran- to fight Iran and Achilles began the war with the Trojans through his mother, and he did not participate in it, so that the Achaemenians would fail.