Abstract: Due to the construction de-watering in the vicinity river , several cracks appearced in an brick and reinforced concrete building and the first floor balcony had unequal settlement , these are mainly previous cracks, the maximum width of the cracks is up to 50 mm, there are no cracks on the main wall. After appraisal, the main reason is that there is a pile foundation under the main structure of the building, but under the first floor balcony there is only the strip footing . The soil layer under the building is underconsolidated soil deposit, during the consolidation, large unequal settlement occurred in the building, the construction de-watering promoted the consolidation, which made the cracks be wider. So using these treatment measures, such as constructing chemical churning piles as the barrier-wall, pasting gypsum on the cracks and so on, at the same time intensive observation of the stability of the cracks and change in underground water level was done. After reinforcement it was observed the settlement again and found on obvious change.