Abstract: In order to make an investigation into the possible difference in coefficient B of saturated clay under high and normal pressures and the relevant contributory factors, isotropic consolidation tests on saturated clay under pressures of 2 MPa are conducted by GDS triaxial apparatus, and a novel test procedure is designed to check coefficient B before and after consolidation. The test results indicate that the reason for unusually small coefficient B of “saturated” clay after high-pressure consolidation is that the soil sample cannot reach 100% ideal saturation, rather than, as reported previously, the majority of the pore water in high pressure consolidation sample being bound water whose physical characteristics obviously differ from those of bulk water. In addition, the complete dissipation of the pore water pressure significantly lags behind the end of the primary consolidation in volume-logarithmic time curve during high pressure consolidation tests on saturated clay, and the process of coefficient B of consolidated clay under high pressure getting to be stable takes much longer time than that under normal pressure.