The impact of consolidation pressure,anisotropy and structures are studied on the permeability of silty clay respectively by using the sixth layer soil in Shanghai.Then the microstructure and permeation mechanism are discussed by using scanning electron microscopy.It is revealed that permeability coefficient decreases with the increase of consolidation pressure;and the horizontal permeability is greater than the vertical permeability;the permeability of remolded soil will decrease when compared with the undisturbed soil.Moreover,the microscopic analysis indicates that consolidation pressure makes the soil more compact;there are many granular polymers in the vertical direction while flaky or planar polymers dominate the horizontal direction.The soil is disturbed and the small particles are filled with large pores.The changes of pore types and contact modes between the granular clay particles are the essential reasons for the macro permeability difference of silty clay.