In this study, an erosion resistance test method for soil specimens in which herbaceous plants were grown was investigated to clarify the erosion control effect of vegetation work against raindrops. The test was conducted on soil specimens made of sandy soil in which seeds of non-native herbaceous plants (KBG) were sown to develop a root system. X-ray CT scanning was used to determine the extent of development of the root system in the soil and the erosion depth during the test. The results showed that the root system and stems of herbaceous plants increased the erosion resistance of the soil and significantly reduced the erosion depth. The test method discussed in this study was found to be very effective in evaluating the erosion control effect of vegetation work against raindrops.