The active species of Cu supported on TiO2, which were prepared by impregnation method with cupric nitrate and acetate, is investigated by means of Cu K-edge XAFS. The XAFS and UV-VIS spectra showed that the H-2 pretreatment of the samples at 473 K brings about the formation of Cu-0 micro particles with several hundred angstroms of particle size, and the particle on TiO2 prepared from cupric acetate is more stable than that from cupric nitrate. It is concluded that the Cu-0 particle with pertinent size, which coexists with cations such as Cu2+, is the active species for NO reduction.