In order to design liquid lens which works in a severe environment such as high temperature and high humidity, several layered liquid systems are investigated. Especially, the change of the interface between conducting and non-conducting liquid layers has been traced by using empirical molecular dynamics simulation and density-functional theory calculation. The stability of the liquid layers at high temperature was evaluated by simulation results such as the density profile of liquid components, their distribution near the interface, the interface thickness and chemical reactivity between them, which depends on the molecular species consisting of liquid and their concentrations. We found that the organic solvent including halogen atoms, alkyl halide, easily penetrates into conducting liquid layer and reacts with its substances, which is added to increase refractive index and density of non-conducting liquid. We also presented an optimized solution including the minimum organic solvent and satisfying the requisites for an optical device.