A 3D two-way coupling simulation method was proposed for the leakage flow and solid displacement of finger seal. In this method, the porous media model was used to calculate the leakage flow field,and the pressure value calculated by the flow field was loaded onto the finite element model for the calculation of the displacement of the seal. Then the parameters of the porous medium model of the seal laminates group were updated, which was used to recalculate the leakage flow. The above steps were repeated until the simulation of leakage flow and solid displacement converge. Using this method, the leakage flow and solid displacement of finger seal with different pressure differences were numerically simulated. The results show that the coupling calculation converges after three iterations. The pressure dropping, leakage and displacement mainly occur in the area around the finger foot,and the maximum displacement of the seal group mainly depends on the radial displacement. When the differential pressure increases from 0.1 MPa to 0.5 MPa, the maximum radial displacement of the seal increases by about 2%, the maximum axial displacement increases by about 400%, and the leakage increases by about 130%.