Abstract: In Merchants Zhangzhou Development Zone,some factory 2# building uses the isolated foundation,holds the strength level and takes the strong hang rolled-earth fill as the foundation.After building-up,the building is unable to use normally due to the serious differential settlement.The differential reasons of serious uneven settlement of its foundation are analyzed in this paper: The silt inside the cofferdam accumulates and its thickness is different due to cofferdam before filling stones into the sea; The bioturbation capacity on the accumulated silt caused by high-pressure dynamic compaction decreases; In the tideland,The pile is not formed,backfilled stone is disturbed and particle losses due to backfilled stone consolidated by high-pressure rotary jetting.They are main reasons of uneven foundation.