Solid-liquid interface is a place where various physicochemical reaction (such as heterogeneous catalyst reaction, wetting, DNA/protein folding etc.) take place and is a system that must be understood in order to regulate chemical reaction or properties. However, unlike other surfaces, the interface is not exposed and the direct observation is challenging. It triggered the active research of computational chemistry that can simulate the interface by controlling the environment at the atomic / molecular level. However, it is still challenging to quantitatively estimate even the wettability, which is the most fundamental concept of the interfacial phenomena. In this thesis, it is covered not only a single simulation method for catalytic reaction, which is one of the representative interfacial phenomena, but also a multiscale method for qualitative and quantitative prediction of the wettability, furthermore, the possibility of applying it to graphene and metal systems is also shown. In particular, in case of the interface where the solid and the liquid coexist, since the size of the system is large and high accuracy is required, the multiscale simulation method is applied. This will provide theoretical guidance to understand the wetting and the chemical reactions of current materials (that is not easy to measure by stability issues etc.) as well as future materials.