Abstract: Based on SWAT model and quantitatively analyses, the impact of different land use types and climatic factors on watershed runoff in different scenarios were studied to reveal the influence of LUCC and climate change on watershed runoff variation. Combined with RCP4.5 and RCP8.5 climate scenarios, the upcoming runoff change of the Lixian River Basin was predicted. Results were as follows: (1) SWAT model performs well in simulating Lixian River basin runoff. The model parameters R2 and Ens were 0.74 and 0.73 respectively in parameter calibration period, and 0.63 and 0.63 respectively in model verification period. (2) The single land use scenario shows that the conversion of farmland into woodland or grassland will decrease watershed runoff, however, the conversion of forest to pasture will increase watershed runoff. The three types of land contributed to the rise of runoff in the order from the largest to the smallest, followed by cultivated land, grassland and forest land. (3) the average monthly runoff increase caused by LUCC was lower than the average monthly runoff reduction caused by climate change in the Lixian River Basin during 2006-2015. (4) Under the RCP4.5 and RCP8.5 climatic scenarios, the runoff in the Lixian River basin shows a decreasing trend during the period of 2021 to 2050, with decreasing rates of 3.6 ×108 m³/10a and 2.15 ×108 m³/10a respectively. This is consistent with the trend of deceleration of the measured runoff of 6.7×108 m3/10a in the Lixian River basin between 1971 and 2015. However, under these two scenarios, the trend of runoff reduction has been some extent decreased, reaching 53.7% and 32.1% respectively for the 1971-2015 deceleration.