Abstract: The rainfall seepage model is of theoretical significance and engineering application value in the seepage theory and assessment of geological hazards. Based on the Mein-Larson saturated infiltration model and unsaturated uniform infiltration model proposed by Lining and other scholars, an unsaturated wetting front model is proposed using the unsaturated soil water characteristics and hydraulic conductivity model proposed by Van Genuchten to analyze the water content, depth of infiltration and suction changing with the rainfall intensity and duration under the assumption of the soil moisture uniformly distributed and changing with depth. Meanwhile through the comparison between theoretical models and Seep/w simulation under different rainfall conditions, the proposed model is found to exhibit advantages in describing unsaturated water flux in loess.