Abstract: For exploring the degradation characteristics of infiltration processes and fractal mechanism in the sloping farmland in a typical small watershed of rocky mountainous area in the middle of Shandong Province, the theories and methods of soil fractal and hydrology were used to analyze the soil infiltration and its quantitative relation with soil particle-size and pore dimension for four kinds of land use types, including sloping land, abandoned farmland, ecological forest, and economic forest. The results showed that: 1) the sequence of soil stability infiltration rate was as follows: sloping farmland> abandoned land > ecological forest > economic forest, and the sequence of soil particle-size and pore dimension was as follows: ecological forest > economic forest > abandoned land > sloping farmland. 2) There were significant positive correlations between the soil particle-size dimension and pore dimension, and both of them had positive correlations with volume percentage of silt and clay, and negative correlations with soil infiltration rate. 3) The Horton model and the power function model were more suitable to simulate the soil infiltration process and infiltration rate in the study area, but Philip infiltration model were not. The conclusions were that the soil in this area displayed a typical fragment of rocky mountainous regions; Due to the loss of the amounts of silt and clay caused by cultivation in the sloping farmland, the uniformity and fractal dimension of soil particle-size and pore distribution were decreased, hence enhancing soil infiltration capacity and decreasing soil water retention capacity.