Abstract: As the interface between pre-stressed sluice pier and anchor-block bottom are usually separated by an elastic cushion layer in practical design, the three-dimensional finite element method was used to compare the displacement, stress distribution, and contact state of the sluice pier neck under different combinations of working conditions by two simulation methods: overall model and contact model. The results showed that the two simulation methods did not change the overall deformation and stress of the pier significantly. The contact model can better describe the nonlinear interface characteristics between the anchor block bottom and sluice pier. The separation design can improve the compressive stress level in the central region of the sluice pier neck, but can improve little at marginal part of the pier neck, when the bottom interface is separated as the pier and anchor-block are subjected to force. When the bottom interface is separated, for the unilateral water discharge condition, due to the spillway pier is in an unfavorable eccentric tension status, the contact model will increase the tensile stresses at the edge of the sluice pier neck, however in bilateral water discharge condition, the tensile stresses at the edge of the pier neck can be reduced. When simulating the connection between anchor-block and pre-stressed sluice pier numerically, it is suggested to consider the stress level of the sluice pier under the unilateral water discharge condition, and attention should be paid to the concrete anti-cracking at the neck edge of the gate pier.