Abstract: Traveling of pigs in oil and gas pipelines presents a complex dynamic process, which is predominantly induced by coupling between sealing disc and pipe walls. To determine the mechanical properties of interaction between sealing disc of bi-directional pig and pipe walls, the 2D axisymmetric finite-element model is established with the finite-element method to determine impacts of shrink range, holding radius and thickness of sealing disc of bi-directional pig deployed in DN200 on contact stress, bending stress and curvatures. Research results show that, given identical holding radius and thickness, contact stress between the sealing disc and the pipe walls increases and then decreases with the increase of shrink range, whereas bending stress increases with the increase of shrink range; given identical thickness and shrink range, the contract stress increases and then decreases with the increase of holding radius, whereas the bending stress increases with the increase of holding radius; given identical holding radius and shrink range, the contact stress and bending stress increase with increase of thicknesses.