(1) Background: Understory planting is a common soil and water conservation farming practice, that makes full use of the natural conditions of the understory, such as soil, climate, and ecosystems, to improve the efficiency of agricultural production.(2) Methods: To reveal the nutrient loss characteristics of understory planting of Gastrodiae Rhizoma, runoff plots were set up in the field, and three surface slopes (5°, 15°, 20°) were designed to collect runoff sediments and compare the soil and water loss between the natural slopes and the slopes planted with Gastrodiae Rhizoma, to investigate the flow and sand production characteristics of understory planting on sloping cropland with different slopes and the loss of nitrogen and phosphorus nutrients carried by it, to provide a basis for the restoration of vegetation cover and the enhancement of soil fertility.(3) Results: The loss of soil and water and nitrogen and phosphorus in forested land planted with Gastrodiae Rhizoma increased significantly compared with that in natural forested land, and the greater the slope, the greater its loss.(4) Conclusions: Planting Tianma should be avoided in areas with large slopes and serious soil erosion, and some soil and water conservation engineering measures can be taken, such as the construction of retaining walls, drainage ditches, etc.to minimize the scouring and erosion of the soil by rainwater.