Applications of molecular dynamic (MD) simulation methods ranging from polarizable potential models in describing interactions among species to a variety of chemical and physical processes in solutions and at interfaces from the late 1980s to the present are reviewed. The main emphasis is on recent advances in the understanding of ion solvation, molecular association, and molecular solvation at liquid interfaces. The species discussed range from monovalent ions to molecular ions such as hydronium and nitrate ions. Also, the computed properties including the potential of mean force, surface tension, surface potential, and the denity profile are outlined.