This study presents a comprehensive analysis of the orthorhombic CsCuO, focusing on its structural, electronic, mechanical, and optical properties, which uses the first‐principles plane wave pseudopotential technique and local density approximation methods based on density functional theory. The derived structural parameters closely match the previously reported experimental data. The calculated results show that CsCuO is mechanically stable and exhibits a certain toughness. Research on electronic properties shows that CsCuO is a direct‐bandgap semiconductor. Charge density and population analysis show that covalent bonds are formed between O and Cu. The optical property results show that CsCuO has good passability to incident light, indicating that CsCuO is an excellent transparent material. In the visible and infrared light regions, CsCuO has a low absorption coefficient, mainly manifested as ultraviolet absorption. Reflection is mainly distributed in the high‐energy region and does not exceed 25% in the visible light region. It can be used in fields that require less light reflection and the manufacture of medical ultraviolet disinfection equipment.