Abstract: It is necessary to monitor the settlement during construction of highways in the soft clay ground because of its characteristics of high compressibility and low strength. The settlement data during the time of filling and surcharge correspond with the geological data of the thick soft soil. They show that the plan of surcharge is necessary, and the effectiveness of the surcharge is obvious. The data also show both the large soil deformation and the high settlement velocity. Slow convergence have negtive effect on the actual surcharge, and it will lead to large settlement at late stage, which is not corresponding to that of the silty clay with middle to high compressibilities. Therefore, other plans are put forward to meet the control requirements.