How Large is the Urban-Rural Income Gap in China?

China's current official official household survey has failed to effectively cover the rural-to-urban migrants, which overstates the income of urban residents and understates the income of rural residents, and then overstates the urban-rural income gap in China. Our survey shows that the urban household survey basically neither cover the migrant households (missing households), nor the migrant workers who have not any economic ties with their rural families (missing persons). Due to these missing, the urban-rural income gap is overstated by 13.65%. If we further consider that the income records made by the rural household survey miss the income information of some persons who are working and living in urban areas (missing records), the urban-rural income gap will be totally overstated by 41.26%. For these reasons, China's urban-rural income gap will be 2.29-2.84 times in 2010, smaller than the official data 3.23 times. This paper also develops a mathematical model to adjust the deviation.