Molecular orientations during physical vapor deposition of various linear long-chain compounds are interpreted on the basis of a simple model for the initial stage of anisotropic crystal growth. In this model, the initial stage involves adsorption from vapor, surface migration, re-evaporation from the substrate, capture into a cluster, re-evaporation from a cluster, and re-orientation, where the anisotropy of the molecules are considered. In addition, two fundamental orientations of initial small nuclei are assumed to be under thermal equilibrium. The set of differential equations for the individual elementary processes can be solved numerically. The calculated results agree well with actual orientational phenomena of long-chain molecules at various substrate temperatures, i.e., a higher substrate temperature results in a higher degree of normal orientation.