[Objective] To explore the regularities of rainfall infiltration in shallow loess, and to provide reference for studying the mechanism of loess landslide caused by rainfall.[Methods] One monitoring site was set up in Dalu Dicth, Shaanxi Province by arranging the monitoring instrument both in cracks and no-cracks at different depths. The observed results were dealt with numerical simulation to analyze the regularities of rainfall infiltration.[Results] (1) Soil moisture was recharged by rainfall and was drained away through evaporation in the area. The main affect of rainfall on water content was the tempo-spatial responses to the rainfall. There had a hysteresis for temporal response, which was more obvious with the increase of the depth. The effect of evaporation on soil water content was influenced by the depth and the exposed area of soil. The greater the depth of soil was, the smaller the effect would be. (2) The soil water content was very sensitive to rainfall, e.g., when precipitation was less than 3 mm/d, the rainfall almost had no effects on the water content of soil, however, when precipitation was 3~40 mm/d, the rainfall was observed having positive effect on soil water content.[Conclusion] The infiltration process simulation under different conditions showed that the effect of crack was little, and also the infiltration depth of loess in study area was limited.