Abstract: Several cracks were found to occur on the slope face of the Laiwushan retaining wall. In order to understand the mechanism of deformation and failure mechanism,automatic monitoring instruments,including piezometers,tensiometers,moisture probes and inplace inclinometers were installed at the top of fill slope. The following findings can be observed based on the monitoring data of piezometers,moisture probes and tensiometers: rainfall infiltration has little influence on the fluctuation of the groundwater table,possibly because the groundwater table was deep； the response of pore pressure and volumetric water content at various depths in the fill was delayed,depending on the soil depth. The rainwater can infiltrate into a depth of over 3m,and a perched water table can be observed at the depth of 3m,resulting in reduction in shear strength of soil and potential shallow failure.