The increasing trend of rural residents' income was slow in recent years in China, and the internal income difference of rural residents has been continuously, steadily, and slowly rising. About 60 percent Chinese people are rural residents at present. The expansion of rural residents' income difference should influence economic rapid and healthy development.The paper summarized theories to interpret rural residents' income difference and math methods to measure income difference, which laid theory base for further analysis and provided empirical materials, it studied general income difference of rural residents by Gini coefficient, Theil index, decomposed Gini coefficient according to income sources, ten equally separated methods and Econometric models, and measured and analyzed income difference and its determinants of rural residents between regions and in LiaoNing Province and NeiMengGu Municipality.The main conclusions are as follows:Although the income difference between three main economic districts lowered in recent years, it is still high. Increasing speed of income difference between provinces is faster than that of general income difference. Income difference between areas is mostly influenced by wages and salaries; Tax expense, regional factors in one province, family structure, labor culture and family possesses played a great role on income difference in LiaoNing Province and NeiMengGu Municipality. Non-agriculture obviously increases income difference. Forestry, fishery and stockbreeding increase income difference. Wages and salaries fairly increase income difference in LiaoNing Province.Appropriate suggestions based on the above conclusions are as follows:Income difference between regions must be emphasized; more agricultural and rural support for poor districts must be given; rural residents with low income must be protected; non-agriculture must be developed quickly; rural redundant labor must be transferred as soon as possible; rural financial system must be improved.Studies on income difference of rural residents are many, which are restricted to only describing income difference and seldom analyzing its determinants that have been systematically researched in the paper. The paper analyzed general income differences, income difference between districts and income difference in one province or municiplity; the analysis of income difference in one province or municiplity was based on family micro-data of LiaoNing Province and NeiMengGu Municipality and comparative analysis was conducted between them. Resource materials of thorough studies on income difference between districts and in one province are a few.