Abstract: Based on the relationship among the void ratio, hydraulic conductivity and effective stress, a formula for the coefficient of consolidation and effective stress is derived. Using a self-developed test equipment to simulate land subsidence and through the analysis of test data, it is evident that the coefficient of consolidation is not constant but becomes small under compression. Considering the non-linear coefficient of consolidation, the Terzaghi’s theory is modified. Analytic solutions are compared with the measured values. The results show that the calculated values of ground consolidation settlement are more accurate by means of the modified Terzaghi’s theory of non-linear coefficient of consolidation.