A new layered oxyselenide, Ba2CuO2Cu2Se2, was synthesized under high-pressure and high-temperature conditions and was characterized via structural, magnetic, and transport measurements. It crystallizes into space group I4/mmmand consists of a square lattice of [CuO2] planes and antifluorite-type [Cu2Se2] layers, which are alternately stacked along the caxis. The lattice parameters are obtained as a= b= 4.0885 Å and c= 19.6887 Å. The Cu–O bond length is given by half of the lattice constant a, i.e., 2.0443 Å. Ba2CuO2Cu2Se2is a semiconductor with a resistivity of ∼18 mΩ·cm at room temperature. No magnetic transition was found in the measured temperature range, and the Curie–Weiss temperature was obtained as −0.2 K, suggesting a very weak exchange interaction. The DFT+Ueffcalculation demonstrates that the band gap is about 0.2 eV for the supposed antiferromagnetic order, and the density of state near the top of the valence band is mainly contributed from the Se 4p electrons.