In the past decade, both Monte Carlo (MC) and molecular dynamics (MD) calculations have been extensively used in the field of chemical engineering thermodynamics for the purpose of obtaining general features of dynamic and equilibrium properties of simple model fluids at the molecular level. The most frequently used model is pure and mixed fluids interacting with Lennard-Jones (LJ) potential. In this review article, some representative results are presented and discussed with particular emphasis on structure (local composition), PVT relation, excess properties and phase equilibria of LJ fluid. The possibility of utilizing these results for physical property prediction is discussed, The present status of application of quantum chemistry-based potential models has also been given.