In order to investigate the soil displacement and pile foundation deformation and internal force distribution characteristics under adjacent construction access load in Nanchang binary strata, as well as evaluate the influence of adjacent construction access load on the safety of existing bridge pile foundations, a series of numerical simulations are conducted via Plaxis 3D. The difference of calculation results between two soil constitutive models of Mohr-Coulomb(M-C) and small strain stiffness(HSS) is compared. Besides, the HSS model is used to analyze the additional deformation and internal force of the existing pile foundation adjacent to the working line under the construction access load, and its safety performance are evaluated. The results show that the influence area of the soil displacement calculated by the M-C model is too large, and the calculation result by the HSS model is much closer to the practical situation. Considering 6 mm as the allowable value of soil settlement, the influence width is 3.2 m beyond the centerline of the construction access. The deformation and internal force of the adjacent existing bridge pile foundation are within the safety range, meeting the safety requirements specified by the codes or standards.