To explore the effect and mechanism of soil physical crust on runoff and sediment yield on the Loess Plateau sloping farmland, so as to provide scientific basis for the prevention and control of soil and water loss on sloping farmland in the Loess Plateau, indoor artificial rainfall simulation experiment was conducted to study the influence of deposition crust on slope farmland and splashing crust formed after ploughing on the production process of runoff and sediment on slope. According to the crust formation characteristics of sloping farmland in the study area, five treatments were designed in the experiment, including bare land, deposition crust, deposition crust destruction, tillage and tillage splashing crust, and each treatment corresponded to two replicates. Taking the 25° slope of Ansai loessial soil as an example, the rainfall intensity was set to 120 mm/h and the rainfall duration was set to 1 h. The results showed that: (1) The deposition crust of sloping farmland promoted slope runoff and inhibited slope sediment yield. After breaking the crust, the total sediment yield was 19.28 times that of the original. (2) After ploughing, the total runoff decreased by 19.91%, but the total sediment yield increased by 14.67%. In addition, after ploughing the cultivated land and forming splashing crust, the total sediment yield was 4.08 times and 9.98 times that of the original, respectively. (3) The cumulative sediment amount increased as power function with the increasing of cumulative runoff. According to the coverage of topsoil crust on sloping farmland, the increase process could be divided into convex increase (crust coverage) and concave increase (no crust coverage). In summary, the deposition crust formed by sediment deposition drying at the ridge or grass belt under sloping farmland should be actively protected. The splashing crust formed by rainfall in the ploughed sloping land should be broken in time.