The result indicates that the Gini coefficient of income inequality rose to 0.453 in 2003 and dropped slightly to 0.443 in 2005 when controlling for cost of living differences. The World Bank report (2009) also indicated that the spatial cost of living makes a difference in measuring income inequality. Adjusting for the spatial cost of living drops the Gini index from 0.453 to 0.411 in 2005. Many studies have found that increasing inequality may be detrimental to economic growth (Persson and Tabellini, 1994, Alesina and Rodrik, 1994, Clarke, 1995, Sabot et al., It is also difficult to explain the coexistence of big income distribution gaps and fast economic growth in the world.