Abstract: Based on the data of farmers’ per capita net income in 86 counties in Gansu from 1988-2012, this paper conducted empirical analysis of the polarization and the spatial inequality of farmers’ per capita net income in Gansu. Results show that: 1） the Gini coefficient and its decomposition imply that the overall regional disparity of farmers’ per capita net income in Gansu is significant; 2） the changing trend of Gini coefficient is not smooth with obvious rises and declines, which are very different from that of the developed areas; 3） the income gap among the five regions displays a decreasing trend; 4） the contribution rate of the gap between regions is increasing and the trans-variation intensity is declining; and 5） the interleaving degree between regions is declining. The spatial polarization degree of farmers’ per capita net income, measured by ER, EGR, and LU indexes, shows that the regional polarization of farmers’ per capita net income in Gansu has significantly increased. Compared with the developed areas, the polarization degree in Gansu Province does not show any decreasing sign and regional balanced development still face serious challenges.