Titania supported palladium-copper bimetallic catalysts (Pd-Cu/TiO2) are prepared by liquid-phase chemical reduction method and then applied in the catalytic reduction of nitrite ions in drinking water. The nitrite conversion and selectivity to N-2 influenced by metal molar ratio (Pd:Cu), H-2 flow rate, CO2 flow rate, pH value of solution and reaction temperature are also discussed in detail with physical characterizations methods such as XPS, XRD, in situ FT-IR. It is discovered that bimetallic Pd-Cu/TiO2 catalyst has higher activity than monometallic Pd/TiO2 catalyst in the catalytic reduction of nitrite ions and a mechanism is proposed to explain this promoting effect of bimetallic catalyst in this paper. (C) 2004 Elsevier B.V. All rights reserved.