The very high rate of labor to land results in the equilibrium state that the contribution proportion of land is high in China and that contribution rate of labor force is low. Since the separation between rural and urban labor markets blocks the non-agricultural transfer of agricultural labor force, a big income gap exists between agriculture and non-agriculture population. Non-parameter Datum-Envelopment-Analysis(DEA) on international agricultural production indicates that China’s agriculture is just on the efficient frontier facets, so there is small space for China to increase income of agriculture population by enhancing efficiency of agricultural production and it is difficult to narrow the income gap between urban and rural areas. The necessary and available way for increasing the income of rural residents is to set up a unified rural-urban labor market and decrease the number of agricultural labor.