The Co-Cu alloy films were prepared using IBAD at various ion incidence angles. The compositions of all films did not vary significantly with the ion incidence angle. The sample prepared under perpendicular ion bombardment was fee structure with composition Of Co83Cu17 and lattice constant of 3.57 &ANGS;. It was easily magnetized in the film plane. Magnetoresistance was performed on all samples at room temperature. The MR ratio was found only in the sample with perpendicular ion incidence. The measured MR ratio is positive and consistent with the magnetization variation under the external field. The full width at half maximum (FWHW) of the MR is narrow about 10-15 Oe. Considering the effect of ion bombardment, we regarded that the interface between the alloy film and the substrate contributed to the positive MR (PMR). There was another conductive mechanism switched in this interface. © 2004 Elsevier B.V. All rights reserved.