The slope of the excavations often has the concrete surface layer and the hardened slope top which is impermeable to water. In order to study the effect of rain type and the length of hardened slope top on the stability of the unsaturated excavations,the rainfall simulation is obtained by GeoStudio SEEP/W module,and the distribution characteristics of the water pressure and volume moisture of the slope after the rain are obtained. Then,the rain simulation results are imported into the SLOPE/W module. The shear strength parameters obtained by the consolidated quick shear test are used in numerically calculation,and the stability of the excavations is evaluated. The results show that the depth of infiltration of instantaneous heavy rainfall is small,and the infiltration depth of ordinary rainfall is large in long periods. The hardened slope top tends to limit the infiltration of rainwater,reduce the infiltration at the slip surface,and is beneficial to the stability of the excavations. When the slope top hardening length is 3 m,the effect of rainfall on the stability of the excavation is not obvious,and when the length is 5 m,the stability of the excavation is basically not affected by rainfall. When the initial water content of the soil of the slope is low,instead of arousing adverse effect on the stability of the excavations,the early rainfall is beneficial to the stability of the excavations. Finally,taking the actual landslide as examples,the simulation results are verified and the importance of slope top hardening to the stability of the slope is explained.