For　further　investigating　the　role　of　components　in　copper-cerium-barium　composite　oxide　catalysts,　a　series　of　noble　metal-free　catalysts　with　different　barium　contents　were　synthesized　by　citric　acid　method.　The　prepared　catalysts　were　characterized　by　X-ray　diffraction,　Brunauer-Emmett-Teller　method,　scanning　electron　microscopy,　Raman　spectroscopy,　and　Fourier　transform　infrared　spectroscopy.　Catalysts　were　evaluated　by　NO　oxidation,　NOx　adsorption,　and　NOx　temperature-programmed　desorption.　The　results　showed　that　barium　content　significantly　affected　the　catalysts＇　properties.　With　barium　addition,　interactions　among　components　considerably　changed;　hence,　the　microstructure　and　performance　of　catalysts　were　distinctly　different.　In　general,　the　interactions　of　barium-copper　and　barium-cerium　were　not　conducive　to　catalyst　adsorption.　Adsorption　performance　derived　from　barium　carbonate　was　superior　to　those　of　the　other　two　components.