We present the molecular dynamic simulation results for the liquid-vapour interface of the pure Lennard-Jones fluid. The thermodynamical properties, the surface tension, the effective thickness of interfacial layer and the mean-square amplitude of capillary waves are determined. Calculations have been performed at cut-off radii of the intermolecular potential r(c1) = 2.6 sigma and r(c2) = 6.78 sigma. It is shown that the cut-off radius of the interaction potential in the two-phase systems should be chosen to be larger than that in the one-phase systems for an adequate representation of properties.