Abstract: A waste-dump in an Open-pit Iron Mine is with a height of 134 m.Its basis is on a silty clay layer with an average thickness of 12.65m，where slope gradient of the font area is slow but steep in the rear area；The maximum gradient in the rear area is 16°.A series of experiments on deformation and failure features of waste-dump slope with its basement in natural and saturated state are conducted by the floor friction model.The evolution process of potential destruction and causes of destabilization are explored as well.The results show that the waste-dump slope with its basement in natural state is stable in whole，and only damaged in bottom.However，the waste-dump slope with its basement in saturated state slides down over the silty clay layer.The potential failure mode of the slope is a combination pattern of slump，tow and shove.Firstly，the first beach in the front of slope becomes unstable and shears over the silty clay layer.Secondly，the area of free face in the second beach increases since the lateral force is decreased.In the same time the slip surface develops from the first beach to the second one.Finally，the slope slides down in whole with the top area decreasing from the tension crack.Then the broken area shoves the top area to the second beach and the lower one.The slope ends up stable with bulging deformation in the front area and decreasing deformation in the rear area.

Key words: Inclined and weak basement, Waste-dump slope, Deformation and failure features, The floor friction model