Abstract: The expansion of citrus orchard is the most important land use change in the Xunwu River Basin in the past 20 years, which has an impact on the hydrological process in the basin. In this study, land use dataset of three periods were used as scenarios, runoff and sediment was simulated with SWAT model at three different land use scenarios. The annual citrus orchard mapping results were used to analysed the impact from citrus orchard expansion together with sediments loadings in Xunwu River. Results showed: The SWAT worked for runoff (Re=-0.05; R2=0.79; Ens=0.72) and sediment (Re=0.75; R2=0.8; Ens=0.71) simulation ; The change rate in runoff and sediment from 2005 to 2015 was 2.57% and 4.27% respectively; The the area of forestdecreased by 36.83% and the area of citrus orchard increased by 42.48% during 1990 and 2015; The area of newly reclaimed citrus orchard has a uncertain influence on the sediment content. This is because river sediment transport is not only related to soil erosion, but also to the location of the soil erosion plots. And the soil erosion can be kept down with the vegetation coverage increasing and the water conservation measures such as back-and-slope ground.