A large amount of granite is distributed in the Longling area of western Yunnan. Its surface weathering is high, and there is a lot of rain, resulting in a severe erosion of the side slope surface and extremely serious soil and water loss. Therefore, targeted soil and water loss control scheme is urgently required. In this study, the weathered sandy soil in the granite distribution area of Longling County, Yunnan Province was considered as the research object and artificially simulated rainfall experiments were designed for three soil and water conservation measures, including engineering, plant, and engineering + tillage measures, and three surface slopes (10°, 20°, and 40°). Three-dimensional laser scanning technology was employed to monitor the effects of soil and water conservation measures under different slopes with high precision and real time, and the effectiveness of soil and water conservation measures was assessed using the characteristics of sediment yield rate and sediment reduction benefit. The experimental results show that the slope is the most important factor influencing slope erosion under certain rainfall intensity conditions; the steeper the slope, the faster the sediment yield rate. The three types of soil and water conservation measures have different degrees of sediment reduction effect. The effect of soil and water conservation of the two combined measures is far superior to that of a single measure.