In this thesis, we employed the first-principle calculations to investigate the interface properties of several hybrid systems using CASTEP code. We focus on the charge transfer behavior and the band alignment of each system. The hybrid systems we used including polythiophene/carbon nanotube, polythiophene/graphene and gold/graphene systems. The electronic structures, such as the binding energy and the intermolecular distance, were investigated and full-optimized. We suggest some factors may influence the charge transfer behavior and the band alignment of different hybrid systems. According to these details, we give some advices on designing devices. The Schottky barrier heights of different metal/semiconductor hybrid systems were also calculated.