In order to analyze the condition of rain infiltration of multilayer soft interlayer stability of bedding slope, based on the theory of saturated-unsaturated seepage and stability analysis theory, the Beijing Zhuhai Expressway (Xiangtan-Changsha section) left a multilayer bedding containing weak interlayer slope as the research object, establish the corresponding multi layer bedding slope numerical analysis model of weak interlayer that of the slope in rainfall seepage characteristics and seepage stability variation conditions. The results of the study show that: The decrease of matric suction in the weak intercalation of the slope under rainfall infiltration was faster and the recovery after the rainfall stopped had a certain hysteresis; The volumetric water content of the weak intercalation in the slope gradually increases to saturation under the condition of rainfall infiltration and then maintains the saturation state to form a transient saturated zone. After the rainfall stops, the transient saturated zone begins to slowly dissipate after a brief period of maintenance, showing "convex" type distribution; The wetting front of the slope mainly extends to the interior of the slope along the weak front of the slope and forms a frontal surface in the weak interlayer, forming a wavy distribution as a whole; The slope safety factor decreases gradually with the increase of rainfall duration, and the rate of decrease is abrupt. Under the condition of rainfall infiltration, the failure and development of multi-layered weak intercalated soil slopes tend to have some traction and mutation.