Afforestation is regarded as an effective ecological restoration strategy for controlling soil erosion worldwide. Although compelling evidence suggests that mixed plantations improve soil fertility and enhance ecosystem stability, their impacts on soil erosion in arid and semi-arid areas remain unclear. Therefore, we conducted a meta-analysis involving 160 observations from 32 publications to evaluate the effects of tree mixtures on soil erosion in the Loess Plateau. The results indicated that, on average, mixed plantations significantly reduced surface runoff by 30.20 % and sediment yield by 40.19 %, respectively. Mixed type and stand age were the predominant drivers of surface runoff and sediment yield changes. These positive mixing effects increased with stand age and were more evident in the tree-shrub mixtures. Similarly, mixed plantations were more conducive to controlling surface runoff and sediment yield increased with slope gradient, but this positive effect decreased significantly with the increase in rainfall and temperature. Moreover, tree-shrub mixtures were more favorable in controlling soil erosion in areas with limited rainfall. Furthermore, mixed plantations control surface runoff while reducing the risk of soil erosion, and mixed plantations could also control soil erosion by reducing soil bulk density (SBD, - 4.5 %) and increasing plant canopy density (PCD, +8.9 %) and soil organic carbon content (SOC, +15.2 %). Our results highlight that soil and water conservation in arid and semi-arid regions can be improved by creating tree-shrub mixed plantations with vertical structural diversity.