Abstract: TiO₂ nano-particles supported Pd catalyst was prepared by impregnation method.The effect of rare earth element La and space velocity on the catalytic performance was investigated by using selective hydrogenation of acetylene to prepare ethylene as reaction model.The catalytic performance of RiO₂ nano-particles supported Pd catalyst and Pd-La/SiO₂ catalyst using nanometer SiO₂ as carrier was compared.The experimental results show that Pd/TiO₂ catalyst has excellent catalytic activity and performance stability.The La promoter remarkably improves the selectivity of ethylene,and the increasing of ethylene selectivity reaches 40%.The optimal space velocity is 18 000 h^-1.The ethylene selectivity on the Pd-La/TiO₂ catalyst is higher than that on the Pd-La/SiO₂ catalyst.