Abstract: Soil bulk density and water infiltration rate were determined under different plant communities in saline-sodic soils in the Songnen Plain.The bulk density measurements showed that there was a significant difference among different vegetation covers.The largest soil bulk density was found under Phragmites australis(Cav.) Trin.ex Steud.and was increased with the increase of sampling depth in soil.On the contrast,the lowest soil bulk density was observed under Leymus chinensis,which was decreased with the increase of sampling depth in soil.The result of water infiltration rate indicated that vegetation covers could increase water infiltration rate.The estimates of water infiltration rate showed a consistent agreement with the actual measured values from 0 minute to 110 minutes.