The present study aimed to consider the role of context in the translation of metaphorical expression from Relevance Theory point of view, by means of think-aloud and retrospection methods; this study attempts to look more closely at the competent translator's interpretations of metaphorical expressions and by scrutinizing the nature of their interpretations, finds some clues to the various mechanisms employed in the interpretation process and find different sources of deviation , and thus answers the crucial ,neglected question of 'what kinds of mechanisms Iranian competent translators deal with in the metaphor interpretation and comprehension'.