The squeezing damage in expansion joints of high-piled wharf is the general weakness in actual projects, which has a serious impact on the normal use of wharf. To solve this problem, combining the practical engineering design of the high-piled wharf, using the finite element method, we study the aperture comprehensively of three states, i.e., extrusion contact, critical contact and no contact of the wharf panel, analyze the variation of internal forces of wharf panel with different post-construction apertures theoretically, and propose a new idea on determination of a reasonable post-construction aperture, which provides the basis for the design of wharf segments and construction control.