In order to reveal the driving mechanisms of Robinia pseucdoacacia plantation and the responses of ecological characteristics of soil moisture to plantation degradation,the soil hydrologic-physical characteristics,infiltration,and water-holding capacity in degraded R.pseucdoacacia plantation in the Yellow River Delta area are studied using the methods of representative field investigation and laboratory analysis.Results showed that with the degradation of R.pseucdoacacia plantation,soil hydrologic-physical properties such as soil organic matter,soil porosity,and void ratio decreased with increased soil density and soil hydrologic-physical properties in the 0—20 cm layer was better than those in the 20—40 cm layer.Soil porosity in slightly,medially and badly degraded stands increased by 3.68%,9.56%,and 14.71%,respectively,compared with normal stand,and however,total soil porosity decreased by 2.38%,4.86%,and 9.57%,respectively.Horton infiltration model can better describe the infiltration process in the degraded R.pseucdoacacia plantation.With the degradation of R.pseucdoacacia plantation,initial infiltration rate and stable infiltration rate decreased greatly.Similarly,stable infiltration rate decreased by 25.62%,55.47%,and 85.07%,respectively,compared with normal stand(4.02 mm/min).Total water-storage capacity deceased by 2.37%,4.85%,and 9.56%,respectively,compared with normal stand(195.78 mm).Soil capillary and non-capillary porosity,water-holding capacity,total soil absorption precipitation,and effective precipitation decreased greatly.Soil water-holding capacity in the 0—20 cm layer was better than that in the 20—40 cm layer.