onvergent and divergent forces that play a major role in determining the quality of national coherence are not isolated concepts but they are variables enjoying mutual or reverse relationships. During history and different periods of time, these forces have had appearances and reflections in spatial-geographical stage affected by political management and historical memories of ethnicities and central government. Recently ethnic conflicts and using ethnic cultures around Iran have become an important aspect of the regional conflicts and disputes. Given this reality that Iranian ethnic groups, particularly the Kurdish nation, are the native people of Iranian geography and they have common historical and cultural roots with the Iranian people, and on the other hand, through historical investigation of the interaction between ethnic groups and central government, we witness a period of time that the divergent forces overcome convergent forces under the effect of ethnic policies of central government, foreign interference, role-making of local elites and so on. Therefore, by using analytical-descriptive method, this research tries to respond the question: What factors have affected the Kurdish nation's convergence and divergence during historical periods? It seems that such factors as ethnic policies, vacuum of power in the central government, interaction of national and local elites, providing the ground for political participation of ethnic groups and foreign interferences have been effective factors in Iranian ethnic groups' convergence and divergence.