An apparatus of a magnetoresistance sensor consisting of a substrate, a conductive unit on the substrate, and a magnetoresistance structure on the conductive unit is provided. The conductive unit includes a first surface and a second surface opposite to each other, and the first surface faces the substrate. The magnetoresistance structure is formed on the second surface of the conductive unit and is electrically connected to the conductive unit. The magnetoresistance sensor has high performance and reliability. A magnetoresistance sensor fabricating method based on this apparatus is also provided.