We studied the effects of rainfall pattern, intensity, and duration on the pore-water pressure in the slope and the spatial variability of the saturated permeability on the spatial distribution of pore-water pressure, water content, shear strength parameters and local factor of safety under rainfall. The results show that the rainfall characteristics have significant effects on the pore-water pressure for a given slope. Affected by the main direction of flow, the effect of the horizontal fluctuation scale of saturated permeability on the variation of the pore-water pressure and the water content is greater than that of the vertical fluctuation scale. The critical slip surface of the rainfall-induced landslide is almost parallel to the slope and the depth of the landslide is small. As the increase of the horizontal fluctuation scale, the depth of the landslide increases. Generally speaking, local factor of safety decreases as the vertical fluctuation scale increases.