A subject of great concern in Persian poetry of the Constitution Age is the concept of 'Nation'. The correct understanding and interpretation of the message of this age, to a great extent , depends on an understanding of its position. There is a sharp difference between what the poets of this age stated and those of their predecessors.  In this article, the concept of 'Nation' is examined under the two parts of Pre-Islam and Post-Islam. The Pre-Islam Iranian were well familiar with such concepts as nation, and race. However, quickly after their acceptance of Islam, their attitudes towards the concept of 'Nation' changed drastically. In general, the major meanings of 'Nation' comprise Islam world, Restoration world, place of birth, and nation world.   The results of this study reveal that the conceptualization of 'Nation' in the Constitution Age Poetry must be different, even though some traditional senses of the concept prevail. 'Nation' in its new sense subsumes  elements like a shift in the role of the government and people, racial and national dependencies, and Iranian identity with all its features.