Abstract: The experiment was done at the soil and water conservation institute of Shanxi agricultural university dealing with the coal-ash infiltration laws of three kinds of density(0.9,1.0,1.1 g/cm³)and three kinds of mixed ratio(1.0∶0.5,1.0∶1.0,1.0∶2.0).The results showed that: 1)with the density increasing,the infiltration rate of coal-ash deceased,and the relationship between density and infiltration rate is a power function;2) the density and surface solidity of the coal-ash increased as the coal-ash mixed with the earth,and its infiltration rate deceased;3) the infiltration rate of two mixed materials is mainly dependent on the medium value diameter,if it's bigger,the rate is also bigger;4) the infiltration process can be expressed by universal empirical formula with the pure coal-ash,and expressed by the universal empirical formula and Kostiakov formula with the mixed coal-ash.But there are small offsets between the experimental and simulated curves with the small density in the secondary phase of infiltration process.The research is importance in reducing dust pollution,decreasing infiltration and predicting runoff amount in the coal-ash storage place.