At three artificial rainfall intensities of 60, 90 and 105 mm/h, soil erosion on a slope of 20° was investigated using a three-dimensional laser scanner before and after rainfall. Results show that the amounts of runoff and erosion increased with the increasement of rainfall intensity, while the influence of increasing rainfall intensity on soil erosion is much larger than that on runoff. The calculated errors for the data of the three rainfall intensities using the three-dimensional laser scanner before and after rainfall were 0.872%, 9.349% and 4.495%, respectively, being less than 10%. At the same time, the eroded position and fragmentation could be observed intuitively. Using the three-dimensional laser scanner is able to calculate the volume and amount of soil erosion in a quick and accurate way, and observe the spatial distribution of soil erosion visually.