Disc infiltrometer with two diameters (diameter of 5cm and 15cm) and two distinctly textured soil (Yangling caly soil and Shenmu sandy loam soil) were used to carry out disc 3D laboratory infiltration experiment under five pressure heads (0，－3，－6，－9，－12 cm). The effects of different disc diameters and pressures on cumulative infiltration were studied. Four methods of estimating sorptivity were applied to calculate permeability of these two soils and their applicability were analyzed according to Vandervaere equation. The results are as followed: the cumulative infiltration capacity of 5cm disc diameter is bigger than that of 15cm disc diameter in the same while. The cumulative infiltration capacity of Shenmu soil is higher than that of Yangling soil under the same pressure. Among these four methods, Haverkamp equation provides the closest estimate to the references for the two textured soil.