Atoms are hold together to form different materials and devices through short range interactions such as chemical bonds and long range interactions such as the van der Waals force and electromagnetic interactions.Quantum mechanics is powerful to describe the short range interactions of materials at the nanometer scale:while molecular mechanics and dynamics based on empirical potentials are able to simulate material behaviors at much large scales,but weak in handling of processes including charge transfer and redistributions,such as mechanical-electric coupling of functional nanomaterials:plastic deformation,fracture and phase transition of nanomaterials.These issues are also challenging to quantum mechanics which needs to be extended to van der Waals distance and larger spatial as well as temporal scales.Here,we make brief review and discussions on such kind of mechanical behaviors of some important functional nanomaterials and nanostructures,to probe the frontier of nanomechanics and the trend to multiscale physical mechanics.