Comparative literature is an important field of study of literature, which expresses the relationship between literature and the world culture of nations. The importance of comparative literature is to explore the origins, currents of thought, human and artistic issues, interactions and cultural exchanges and clarifies the literary, historical and cultural and even the political and social relations of each nation with other nations. In the comparative literature, the discussion is about mutual effectiveness, which leads to the unification of human thought. Ahmad Shamlou is a contemporary Iranian poet who has a particular approach to poetry. He has always expressed humanitarian, romantic and revolutionary ideas in form of poetry. Most of his poetry, in terms of content, is a kind of social and philosophical thinking which is distinguished through allegory and the use of symbol and myth. This article compares the contents of Ahmad Shamlou poetry with poetry by French poet Louis Aragon and seeks to answer the question of whether the similarity of content and subject matter in their poems is due to the intellectual affinity and can be due to the common thoughts of unconscious of   human or it is posing  the issue of their influence  on each other.