Self-assembled monolayer of normal hexatriacontane (n-C36H74) is formed at the interface between a solution of n-C36H74 in dodecane and a reconstructed Au(111) surface. Two kinds of lamellae have been observed, in which the long axis of n-C36H74 molecule is either perpendicular to or tilted 63.50 to the trough of the lamellae. The packing structures in both kinds of the lamellae are different. Theoretical calculations based on molecular mechanics have been performed to elucidate the ways of the molecular packing in the self-assembled monolayers on gold.