The effects of earthworm casts on soil aggregate composition, water-erosion stability and water transport characteristics during infiltration were studied by indoor soil aggregate composition analysis and one-dimensional soil vertical infiltration test. The results showed that:(1) The earthworm casts could effectively reduce the soil bulk density and increase the number of large aggregates of 0.25~2 mm. The fractal dimension D decreased from 2.84 to 2.65 by 6.69%, improving the water-resistant stability of soil aggregates significantly. (2) When the application ratio was 1/20, the migration distance of the wet front could be significantly increased, and then the wet front distance was reduced to some extent as the application ratio increased. But both were larger than the treatment without earthworm casts. The relationship between the wet front migration distance and the infiltration time under each treatment could be described by a power function. (3) The increase of the proportion of earthworm casts could significantly increase the cumulative infiltration amount and infiltration rate. When the ratio was 1/3 at the same time, the cumulative infiltration amount increased by 48.74% compared with the non-applied. The Kostiakov-Lewis model had the highest simulation accuracy, which simulated value was closer to the measured.