The ecological environment has been substantially improved by the implementation of Grain-for-Green Project since 1999 in the Loess Plateau. However, there are some obviously regional differences in impacts of Grain-for-Green Project on rural social economy. In this study, Fengxiang (suburban) and Lujiagou (rural areas) towns in Dingxi City were selected as study areas. The data reflected the agricultural and rural income structure from 1998 to 2015 were analyzed by using the repeated ANOVA, spearman rank correlation, and principal response curve analysis to explore the response of changes of rural economic structure and income to Grain-for-Green Project, and to determine the relationship between land use change driven by Grain-for-Green Project and rural income. The results of this study showed that (1) the Grain-for-Green Project had an explanation of 70.4% variation for agricultural income structure of Fengxiang and Lujiagou towns. The planting structure has been changed from wheat to corn or potato by the implementation of Grain-for-Green Project, which led to the changes of the agricultural income structure. (2) The Grain-for-Green Project had an explanation of 54.1% variation on rural economic structure of Fengxiang and Lujiagou towns. The rural income of Fengxiang town was significantly higher than that of Lujiagou town. The influence that the Grain-for-Green Project to rural economic structure of Lujiagou town, which main industry is agriculture, was smaller than that of Fengxiang town, which the percentage of non-agricultural (such as industry, service industry, and commerce & catering industry) industries' income in rural annual income has been increased with the reduction of agricultural percentage. (3) The planting structure has been changed by the implementation of Grain-for-Green Project, which has narrowed the income gap between Lujiagou and Fengxiang towns. (4) The increase of terrace area and the planting areas of corn and potato has increased the net income of rural residents. In view of these, when further performing the Grain-for-Green Project in the future, the status of local economic development with regional variations should be considered, the farmers should be taken part in the ecological management, and the forestry, stocking raising, and non-agricultural industries should be developed with the agricultural development to realize the harmonious development between ecological environment and rural economy in the west Loess Plateau.