[Objective] The soil erosion resistance and the soil erosion processes in the arid valley region of southeastern Xizang under different rainfall conditions were simulated to provide a scientific reference for soil erosion prevention and control and ecological protection in this area. [Methods] Artificial rainfall simulation experiments were conducted with two rainfall intensities （30 and 60 mm/h） and three slope gradients （20°， 30°， and 40°）. The dynamics of runoff and sediment yield on the slopes were systematically analyzed to reveal the mechanism of the soil erosion process on slopes in the arid valley region. [Results] Soil aggregates on the slopes in the arid valley region of southeastern Xizang were predominantly large particles （>2 mm）. The soil cohesion was 18.39 kPa， and the internal friction angle is 24.7°， indicating a certain potential for erosion resistance in the region’s soil. The structural stability of the soil in this arid valley region primarily depended on the composition of aggregates and their mechanical properties. Under 60 mm/h rainfall intensity， the initial runoff generation time on the 40° slope was shortened by 44% compared to that under 30 mm/h intensity， indicating that the combination of steep slopes and heavy rainfall significantly accelerates surface runoff formation in this area. As slope gradient and rainfall intensity increased， both the total runoff yield and runoff rate on the slopes increased significantly. Regarding the sediment yield process on slopes in the arid valley region of southeastern Xizang， compared to the 30 mm/h rainfall intensity， the 30-minute cumulative sediment yield on 20°， 30°， and 40° slopes under the 60 mm/h intensity increased by 195.9%， 232.5%， and 282.0%， respectively. Under different rainfall intensities， the variations in sediment yield and sediment yield rate for the same slope type vary greatly. [Conclusion] Although the soils in the arid valley region of southeastern Xizang possess a stable structure and good erosion resistance， the combined effect of steep slopes and heavy rainfall is the key trigger for severe soil and water loss. Targeted measures need to be taken to reduce runoff and protect the surface.