One of the most differences among Developed, Developing and underdevelop countries is the difference in their income distributions. The income in developed countries are generally distributed in a fairer manner comparing to the, developing and underdeveloped countries. Beisides this income inequality has risen in the interval of 1980-2000, across the globe and in all of the countries except from the Nort Asian countires. The income inequality has risen in OECD countires in the interval of 1980-2005 averagely for two points. However the difference of inequality between the countries is much bigger. Indeed, primary income distribution is too bad in most counties which are fairly beter in terms of income inequality. Primary income distribution is improved by social intervention. OECD countries are trying to decrease the income inequality by tax and transfer policies. However, it is necessary to stop the rising of the difference between the capital incomes and the wages which is the real reason in the base, in order to decrease the income inequality.