A method for mounting an aircraft pylon connected to a wing includes: a step of pre-positioning first and second contact surfaces respectively provided on the wing and the pylon, a step of installing and tightening temporary connection elements, so as to keep the first and second contact surfaces clamped against one another, a step of installing and expanding at least one radially expandable element in at least one pair of first and second receptacles respectively provided on the wing and the pylon, a step of installing and tightening final connection elements connecting the pylon and the wing in the mounted state, a step of removing the radially expandable element(s) and the temporary connection elements, and of installing the remaining final connection elements and shear pin(s).