Abstract: Based on the remote sensing image interpretation in 2000, and combined with hydrology and water resources data, this paper evaluates optimal allocation of the soil and water resources in quantity and spatial configuration. On this basis, it simulates the land use change scenarios in Xianyang loess hilly areas through the application of binary logistic regression, CLUE-S model and SPSS 19.0 statistical analysis software. The results are shown as follows. (1) From the quantity results of optimal allocation of land and water, it is indicated that arable land, grassland, water area and unused land are decreasing, while the woodland and construction land areas are showing an increasing trend. (2) From the point of view of ecology, the results of optimal allocation of the soil and water resources in the loess hilly areas can reflect ecological value and economic benefits of land ecosystem. It is estimated that the ecological benefits would increase from 153.13 million yuan in 2000 to 154.45 million in 2020, and the land economic benefits would rise from 6.84901 billion to 7.19021 billion yuan in the 20 years. (3) From the results of spatial optimal allocation of water and land resources in the past 10 years and the next 10 years, we can come to a conclusion that the construction land has increased dramatically, and the increased area is mainly concentrated in the surrounding areas of original construction land. The areas with most significant construction land changes are mainly concentrated in the Qindu District of Xianyang city and Sanyuan county.

Key words: CLUE-S model, loess tableland areas, optimal allocation of water and land resources, spatial simulation, Xianyang