The electronic structure and optical properties of CdGeAs2 were calculated by the first principle method using ultra-soft pseudo-potential approach of the plane wave based upon density functional theory(DFT).Mulliken population analysis showed that atomic orbital hybridization occurs when forming chemical bonds.The relationship between inter-band transition and optical properties was analyzed to provide a theoretical basis for investigating or controlling CdGeAs2 crystal defects. The electronic structure and optical properties of CdGeAs2 were calculated by the first principle method using ultra-soft pseudo-potential approach of the plane wave based upon density functional theory (DFT). Mulliken population analysis showed that atomic orbital hybridization occurs when forming forming chemical bonds. The relationship between inter-band transition and optical properties was analyzed to provide a theoretical basis for investigating or controlling CdGeAs2 crystal defects.