Based on the monitoring data of the temporary cofferdam project on the south bank of the Dalian Bay immersed tube tunnel, a numerical calculation model for the plastic concrete interlocking pile anti-seepage wall was established. The accuracy of the model was verified through measured data, and the deformation evolution law of the interlocking pile anti-seepage wall under different influencing factors was analyzed. The conclusion shows that the water pressure has a more significant impact on the deformation and internal force of the interlocking pile compared to soil pressure. The increase in the water pressure leads to the deformation and bending moment of the pile body, which disturbs the soil of the temporary cofferdam; The influence of the soil slope is relatively small, but the soil slope should gradua-lly decrease and not be less than 1∶1.5. The change in pile length has a significant impact on the deformation, with shorter piles that not embedded in the rock and longer piles experiencing maximum displacement at the top of the pile. As the pile diameter increases, the deformation of the pile top and the maximum bending moment gradually increase, and the distribution of bending moments is relatively consistent.