A multiscale particle method for coupling continuum and molecular models is described. In this method, the continuum model was assumed to be in a lattice form and can be applied in noncharacteristic areas or far away regions from the large deformations to save computational time. Defining a series of critical energies for different lattice sizes is convenient for lattice refinement. In the thermal equilibrium case, the efficiency is around 6 times higher than that of a classical molecular dynamics (MD) simulation; in addition, great numerical precision is achieved. To test the connection at the molecular/continuum interface, a large deformation case and a surface friction case were studied in the nanocontact and the nanosliding processes, respectively. The results were compared with the MD simulation and showed great precision. The deviation could be further reduced through a moderate adjustment of critical energies on the lattices, showing that this method is a seamless treatment technology.