Abstract: The equation of lattice vibration of one-dimensional monatomie lattice and the equation of longitudinal vibration of a uniform bar are discussed. Raplaeing the spatial derivatives by spatial differences in the equation of the latter, we get the equation of the former. The dispersion laws of the two systems are compared. The Brillioun zone of discrete system is intimately connected with the interpartiele distance. With the changing of mass distribution from diseretization to continuum, the dispersion law of the lattice vibration changes to that of the longitudinal vibration of a uniform bar.

Key words: lattice vibration, dispersion law, one-dimensional monatomic lattice, uniform bar