A Pd-Cu-Ni alloyed hydrogen membrane has fabricated on porous nickel support formed by nickel pow-der. Porous nickel support made by sintering shows a strong resistance to hydrogen embrittlement and thermal fatigue.Plasma surface modification treatment is introduced as pre-treatment process instead of conventional HCl wet activa-tion. Nickel was electroplated to a thickness of 2μm in order in to fill micropores at the nickel support surface. Palla-dium and copper were deposited at thicknesses of 4μm and 0.5μm, respectively, on the nickel coated support by DCsputtering process. Subsequently, copper reflow at 700℃ was performed for an hour in H2 ambient. And, as a result Pd-Cu-Ni composite membrane has a pinhole-free and extremely dense microstructure, having a good adhesion to theporous nickel support and infinite hydrogen selectivity in H2/N2 mixtures.