When the influence of rainfall on the stability of landslide is analyzed，the sliding-body soils are roughly regarded as fully saturated ignoring the rainfall intensity and duration. In this paper，based on the theory of one-dimensional vertical infiltration of unsaturated soils，considering the connection of parameters of the Green-Ampt infiltration model and the Philip infiltration model，those models were improved. This new method not only deals with the defect that the explicit form can not be expressed with time t as independent variable using the Green-Ampt infiltration model，but also solves the problem that the depth of wetting front can not be calculated separately using the Philip infiltration modelod. Which provides a theoretical basis for the stability analysis of landslide disturbed by the rainstorm. A case study of a soil landslide induced by the action of 50-year continuous 3 d rainstorm in Chongqing was carried out. The improved Philip infiltration model was used to calculate the saturated wetting front depth，landslide stability coefficient and landslide thrust.The results was compared those from the empirical method that sliding-body soil was fully saturated. The research shows that the landslide stability coefficient is significantly improved，while the landslide thrust is significantly reduced. The improved model can provide reference for landslide stability analysis and design.