Molecular mechanics simulations have been performed to predict the response of boron−nitride nanotubes encapsulated with different numbers of C60 fullerenes (C60@BNNT) during the torsional course. A small number of fullerenes induce a local force to the tube wall and result in an earlier collapse of the tube. But when tubes are filled with a larger number of C60 molecules, the critical angle of the final global buckling is found to be greatly increased. An obvious decrease of the strain energy and vdW energy is observed at the onset of the global torsional buckling. The higher global buckling angles of BNNTs encapsulated with a larger number of foreign particles are attributed to the requirement of the extra energy to break the stable composite structure.