An X-ray diffraction and computer-simulation study of Cu-Ti metallic multilayers is presented. The results show Cu-Ti artificial metallic multilayers made by magnetron sputtering technique are metallic superlattices with high structure order. An obvious even extinction phenomenon on the X-ray patterns was found and used in the analyses. Taking into account the structural coherence length perpendicular to the layers and the layer-thickness fluctuation in every period, the calculated X-ray diffraction curves are in good agreement with those measured.