Abstract: In the eastern coastal area of China, the effect of seepage flows caused by dewatering and excavation on the pit deformation and stress cannot be ignored. The relevant terms of national norms for the embedded depth of multi-pivot supporting system have become increasingly unsuitable to the current design requirements. Aimming at this problem, the determination method for the embedded depth of multi-pivot supporting system considering the effect of seepage flows in soft soil area is discussed. The proposed controlling index to determine the embedded depth is put forward. Combined with the monitoring results, a conclusion on whether to consider the effect of seepage flows in the excavation deformation and stress analysis is drawn.