Abstract: Ion-absorbed rare earth mines tend to cause landslides when the injection strength is too high, so it is of great importance to study the intensity of critical liquid injection. The relationship among the percentage of injection area and the critical injection intensity as well as the shear outlet height of landslide under three operation conditions was calculated by the GeoStudio software according to the related soil parameters of surface soil layer, raw ore layer and tailings layer tested on the spot. Experimental data indicates that the critical injection intensity decreases rapidly, and then tends to be slow gradually. The shear outlet height of landslides increases rapidly with the increasing of the percentage of liquid injection area. It increases lightly when the percentage of injection area is higher than 60 %. The critical injection intensity of the ore body increases by 4.8 to 7 times when the tunnel liquid collection engineering is employed. Mineral-leaching has little effect on the shear outlet height of landslides. However, the height will increase about 18 % when the percentage of liquid injection area is higher than 50 %.