Understanding sedimentation and runoff variations caused by land use change have emerged as important research areas, due to the ecological functions of landscape patterns. The aims of this study were to determine the relationship between landscape metrics (LMs), runoff, and sedimentation and explore the crucial LMs in the watersheds on the Loess Plateau. From 1985 to 2010, Grassland (GRA) was the dominant landscape in the Tuweihe (TU) and Gushanchuan (GU) watersheds. Unused land (UNL) and farmland (FAR), respectively, experienced the greatest transformations. The landscape in the study area tended to become regular, connected, and aggregated. The landscape stability of the TU watershed was higher than that of the GU watershed. Annual runoff and sedimentation gradually decreased and significant relationship was found between them (P <0.01). Due to larger FAR area and lower landscape stability in the GU watershed, the sedimentation of the two watersheds were similar, even though the runoff in the TU watershed was greater. The LMs had more significant effects on runoff than that on sedimentation yield. Shannon’s evenness index and the patch cohesion index had the greatest effects on runoff and sedimentation, making them the key factors of influencing water and soil loss. which could provide a scientific basis for the prevention and treatment of soil erosion.