Based on Hamaker's hypothesizes and Lennard-Jones potential, a model of rigid sphere-panel nano-contact was presented to solve microcollision and nanocontact problems. The adhesion equations between the sphere and the first layer atoms or the N layer atoms of the panel were obtained by a continuum method. It is shown that the Hamaker's micro continuum medium principle is held only as the interaction distance 7 times greater than the atomic radius.