[Background] Gangue is an undesirable material generated during shaft building, coal mining, and coa lwashing. Gangue is dug out from under ground and piled up on the surface, which is called gangue dump. Because of the harsh site conditions of gangue dump, the recolonization of plants is very difficult. [Methods] In order to prevent erosion and facilitate revegetation in coal gangue dump, the volumetric water content and runoff of a coal gangue slope under natural precipitation were monitored for 2 years. The coal gangue was evenly spread on the 38° runoff plot and formed a slope with a depth of 70 cm. The base of the slope was impermeable,and the surface and groundwater runoffs were collected separately1 day after each rainfall event. The effects of natural precipitation and weathering on volumetric water content and runoff were tested. [Results] 1) On average, during each light rainfall event(<10mm/d), 0.014 mm surface runoff and 0.019 mm groundwater runoff were produced,i.e., the amounts of surface and groundwater runoffs were similar, and a small amount of surface and groundwater runoffs were generated on coal gangue slope. Moderate rains happened at the highest frequency and accounted for most surface runoff. In each moderate rainfall event (10-25mm/d),0.117 mm surface runoff and 0.962 mm groundwater runoff were generated, meaning that more precipitation was discharged as ground water runoff. While heavy rains occurred at the lowest frequency and accounted for most groundwater and total runoff, during each heavy rainfall event(>25mm/d), 0.254 mm surface runoff and 4.253 mm groundwater runoff were generated. 2) The amount of surface runoff was positively correlated to precipitation, and the amount of groundwater runoff was positively correlated to maximum precipitation intensity and mean precipitation intensity. However,the correlation between precipitation intensity and surface runoff was not significant, which probably resulted from the fact that the infiltration rate of coal gangue was generally higher than the precipitation intensity. The correlation between precipitation and ground waterrunoff was also not significant. 3) In 2014,due to the increase of weathering, the amounts of surface runoff, ground water runoff and total runoff during each light rainfall event decreased by 50%, 100% and 80% respectively, compared to 2013. During moderate rainfalls, they decreased by 88%, 82% and 97% respectively. 4) Coal gangue held a certain amount of water, and the volumetric water content in 20-30 cm coal gangue was the most. Volumetric water content in 10-30 cm ones increased as gangue weathered despite less water input from precipitation in 2014, indicating water holding capacity increased. Even though gangue in 10 cm was highly weathered, the water content was low because of high evaporation rate. 5) Because of its coarse texture and high in filtration capacity, the surface runoffs on the coal gangue slope during light, moderate and heavy rainfall events were 4%, 26% and 19% of those on the soil slope respectively. [Conclusion] This research will guide the practice of soil and watter conservation in gangue dump.