This paper presents a multi-scale modeling approach involving interfacial interactions to predict the elastic properties and mechanical behavior of single-layer graphene-reinforced nanocomposites under tension load. A multi-scale model was developed using the finite element method of the tripartite structure consisting of graphene in epoxy, the interfacial region and their Van Der Walls interactions. The effect of graphene chirality was investigated by proposing a methodology of graphene-Van Der Walls interactions-polymer with determined geometric dimensions. Parametric modeling was performed to model the interactions between Van Der Walls, graphene and interface material atoms using the finite element method with molecular mechanics approach. Numerical analysis of graphene nanoparticles by embedding them in an epoxy with their real dimensions is not an appropriate task today. In particular, it is not possible to analyze these real graphene nanoparticles as multiple by randomly dispersing them in the epoxy polymer. Therefore, in this research, a model was developed to overcome this problem and to investigate the effect of molecular interactions on loads in different axes. The results show that graphene nanocomposites in armchair geometry give higher stress values and behave more rigidly. As the volume ratio increases, the mechanical performances increase. It is seen that the graphene direction is much stronger than the thickness direction. It is clear that the volume ratio effect in the thickness direction has a slight effect on the tensile behavior.