Abstract: It is of great significance for soil erosion control and ecological environment management to study the influence of different land use patterns on runoff and sediment processes in the basin. Based on the measured monthly runoff and sediment data from 1996 to 2003, the SWAT model of Xixian watershed is established. According to the simulation results of SWAT model, the contribution rate of runoff and sediment yield to the whole watershed under different land use types is calculated. Then, the runoff and sediment yield simulation data of each sub-basin of SWAT model are used as the output variables required by the random forest regression model, and the random forest regression model is used to evaluate the importance of different land use types to runoff and sediment processes. The results show that:（1） The SWAT model has high accuracy. The decisive coefficient R2 and Nash coefficient NSE of runoff and sediment rate in the regular and verification periods are greater than 0.75, and the percentage of deviation PBIAS is-1,-5.6 and 5.1, 9.6. The model is suitable for runoff and sediment simulation in Xixian watershed；（2） The contribution rates of land use types to runoff and sediment processes in the basin are in the order of woodland ＞ dry land ＞ paddy field ＞ grassland and dry land ＞ paddy field ＞ grassland ＞ woodland.（3） The decisive coefficient R2 of each stage of the random forest regression model is basically greater than 0.5, and the fitting effect is better; the order of the importance of different land use types to the runoff and sediment process obtained by the random forest regression model is basically the same as the order of the contribution rate of different land use types to the runoff and sediment process calculated by the SWAT model, indicating that the SWAT model is used to calculate the contribution rate of different land use types to the runoff and sediment process. The accuracy is high. In summary, the contribution rate of cultivated land to runoff and sediment in Xixian watershed is the largest. The method of this study can also be applied to other watersheds to obtain the contribution rate of runoff and sediment of different land use types in different watersheds, and provide a reference for the efficient soil and water conservation in the watershed.