The macroscopic and microscopic sealing characteristics of the plane strain model and the axisymmetric model were analyzed aiming at the problems of the unclear differences in computational results between the two models in reciprocating seal studies. The fluid domain model, microscopic contact model, and deformation equations of the sealing interface during reciprocating motion were solved by using a numerical iterative approach. A detailed comparison was conducted between the two modeling methods in terms of contact pressure, oil film pressure, and friction-induced leakage under a macroscopic zero tensile strain condition. Results show that both models exhibit similar computational trends and yield comparable leakage rates. However, the static contact pressure, oil film pressure, and friction force obtained from the plane strain model are lower than those from the axisymmetric model, as the plane strain model does not account for the negative tensile effect during the compression process.