Abstract: In the simulation of nano-scale electronic devices, molecular models contain lots of atoms. It is difficult to edit a model with so many atoms. When a model consists of two or more different materials, editing the interfaces is even harder. Based on the geometry features of general device models being used for simulation, a new model construction method is proposed. It is based on the pre-constructed structures of different materials and the corresponding interfaces. In the design process, users only need to generate simple graphic objects, assign material properties and combine them to form a single object. Based on these graphic objects, together with the corresponding material information, the proposed method can select suitable pre-constructed interfaces to generate required models. According to the results from the user study, the new method is more efficient than current modeling methods.