To study the permeability of saturated clays with different stress histories under ramp loading, the one-dimensional consolidation and seepage tests are carried out using modified GDS triaxial apparatus, and the change of the permeability coefficient of remolded silty clay in Luochuan, Shaanxi Province is studied. The results show that permeability coefficients of normally and over-consolidated saturated clays decrease nonlinearly with the increase of the consolidation stress, and the void ratios of these two soils are consistent with the trend of change of the permeability coefficients with the consolidation stress. The compressibility and permeability of soil in the overconsolidated state are much smaller than that in the normally consolidated state. The permeability coefficient and void ratio decrease with the increase of the osmotic pressure difference under a constant consolidation stress. Finally, the measured values are compared with the permeability coefficients calculated by the modified Darcy permeability coefficient formula, modified Kozeny-Carman formula, Stokes porosity permeability coefficient formula and degree of consolidation and seepage formula in Ref. [12]. The results reveal that the permeability coefficients calculated using the modified Kozeny-Carman formula are in good agreement with the measured values. Therefore, the modified Kozeny-Carman formula is recommended to predict the permeability coefficient of Luochuan saturated clay.