Palladium-copper bimetallic catalysts supported over different supporters were prepared by chemical reduction method, and their catalytic performance was investigated with the hydrogenation of nitrate ions in drinking water under mild conditions. The results show that Pd-Cu/ZSM-5 bimetallic catalyst has the highest catalytic activity among all used catalysts. In addition, nitrate conversion influenced by metal content, metal molar ratio (Pd:Cu) and the addition of CO2 are also discussed. It is well established that the addition of CO2 has changed the reduction path of the intermediate nitrite, but is no influence on the steps of nitrate-to-nitrite reduction. In the end, the mechanism of catalytic nitrate reduction was discussed on the basis the literature results.