In order to better conduct the early safety warning of slope and explore the displacement evolution during the heavy rainfall, the influences of rainfall intensity and rainfall pattern on the temporal and spatial distribution of slope displacement were studied taking the heavy rainfall on 20, July 2016 in Tianjin as the example, and based on the saturated-unsaturated seepage theory and 3D FEM. The results showed that the degree of influence on slope displacements varies with rainfall intensity and rainfall pattern. The influence of rainfall pattern on slope displacement could attribute to the instantaneous rainfall intensity and the cumulative antecedent rainfall. During the process of a typical short duration high intensity rainfall, the time of the surface soil entering the saturation state is positively correlated with rain intensity. The dissipation of the pore water is negatively correlated with the seepage path length. The support structure will slow down the infiltration of the pore water. This study provides guidance for the early stage warning of the slope under heavy rainfall and drainage design of similar projects.