SnO2 and Cu-SnO2 thin films were fabricated by the sol-gel method. The influence of annealing temperature and copper addition on the morphology and microstructure of the films was studied using X-ray diffraction (XRD) and UV-Visible, respectively. The results show that the tetragonal rutile phase is evidenced by XRD with no other phases observed. The crystallinity of SnO2 and Cu-SnO2 thin films had been improved with the increasing annealing temperature. The grain size decreased after Cu doping. On theoretical, Pure and Cu-SnO2 were calculated by first-principles full potential linearized augmented plane wave ultra-soft pseudo-potential method to investigate band structure.