On the basis of the analytical frame of discrimination, the thesis establishes a model of transfer of rural labour forces into city, and researches the impact of rural labour forces transfer on urban-rural income. The results show that the transfer of rural labour forces into city can increase urban-rural income and bridge the income gap between city and village to a certain extent. However, the capital stock of city in China is greatly more than that of the village, so the rural labour forces transfer cannot eliminate the urban-rural income gap completely. In order to elevate the rural income level in China and narrow urban-rural income gap, the government should paint a picture with two brushes at the same time: on one hand, the government should promote the transfer of rural labour forces into city, and change the status quo of dual urban-rural labour forces market structure; on the other hand, the government should increase the input in rural areas and promote the increase of rural capital stock so as to further increase rural residents' income in the process of labour forces transfer.