Abstract: A porous ceramic honeycomb is coated with active Al₂O₃, On this ceramic honeycomb several active ingredients are supported forming a multicomponent catalyst with the composition of La, Ba, Cu, Ni, Mn and trace of Pd. The activity of this catalyst has been tested in the laboratory and by the engine stand. The conversions of CO and HC by using of engine stand are 90% and 80% respectively, and at souitable condition of A/F ratio the catalysts can reduce CO, HC and NOx simultaneously.