Abstract: In this paper,based on three field tests of erosion rate with artificial and natural loess,influence on erosion rate of loess slope cave caused by precipitation is analyzed,and the relationship between erosion ratewater and water volume carried into cave of the same time quantum is studied.The test results indicate that the erosion rate of artificial loess cave is increased with the increase of flow velocity,and for the natural cave,the regularity is opposite. In the same time quantum,erosion rate of loess cave is decreased with the increase of the water and water volume carried into cave.Compared with rainfall,hysteresis phenomenon can be found for the erosion rate.