Systematic examination of Cu2O super cell with and without oxygen defects by using DFT method in SIESTA package. Structural, electrical, optical and HOMO-LUMO properties of Cu2O super cell was analyzed by Generalized Gradient Approximation (GGA). From the band structure, we observed that the removal of oxygen tends to decrease the band gap. The electronic properties such as HOMO-LUMO energy level, ionization potential and electron affinity were studied in DFT method. It was observed that the absorption coefficient was decreased with increasing of oxygen vacancies.