Abstract: In order to meet the development requirements of large-tonnage deep-water wharfs, a new type of wharf, covered sheet-pile wharf, is proposed. The introduction of barrier piles behind the retaining wall significantly complicates the working mechanism of wharf structures. By means of numerical simulation, the impact of following two factors on the working state of the wharfs is investigated: the distance between barrier piles and retaining wall (abbreviated to distance) and the stiffness of barrier piles. The results are as follows: the distance has great influence on the internal force of retaining walls, and it determines the capacity of the barrier piles to relieve the earth pressure on the retaining wall and hence the stability of the whole wharf. The influence brought by the distance will be weakened by its increase. Increasing the stiffness of the barrier piles will be helpful to counteract the deformation of earth.