Cu(2wt%)/ZrO2 shows a high activity for catalytic NO decomposition with CH4 at 873 K. Cu K-edge XANES results show that Cu2+ ions were reduced to form Cu+ after the reaction, and, metallic Cu-0 was scarcely seen. It is concluded that the redox of the Cu ions (Cu2+ reversible arrow Cu+) plays an important role for NO- CH4 reaction.