: The damage production induced by swift heavy ion irradiation in bilayer graphene (BLG) is investigated by molecular dynamics method. By given energy to a cylindrical region, the carbon chains even nanoholes can be produced, which depends on the electronic energy loss (dE / dx). For BLG, the minimum value needed to generate defects lies in 5 – 7 keV / nm. A low density core and a high density shell structure can be seen while the radii of tracks are obtained. With increasing the values of dE / dx, the track radius is fi rst increasing and then saturates. The analysis of defects indicates that only a small part of the defects can be recombined and the radiation damage in BLG is less severe than in single layer graphene.