Post-war reconstruction of Middle Eastern countries is often the outcome of the interactions of internal and external factors. From the perspective of state and social relations，the imbalance between the federal democratic system established under the leadership of external forces and the social relations in Iraq fundamentally affects the process of national reconstruction. This paper analyzes regime transition was inappropriate for Iraqi socioeconomic conditions in terms of state and nation reconstruction. By observing the history of western countries，it is obvious that the establishment of democratic system in western countries is based on the long-term formed viable political system and modern civil society. Comparatively，the historical transformation of Iraq is based on the social structure of sectarian and ethnic diversity. Therefore，by analyzing the relationship between the current political system of Iraq and its historical tradition，social structure，people's cultural identity，economic development and other factors，this study reveals the fundamental reasons why the reconstruction of Iraq has been in trouble and undergone twists and setbacks.