Abstract: The GMR sensors array based on the GMR multilayers were fabricated by photolithography,ion beam etching and lift-off technology as well as protected by SiO₂.This sensor array could be used to detect multiple biomarkers simultaneously.We also investigate the immobilization and detection of protein by the sensors.After the SiO₂ surface was processed by O₂ plasma and PEI,Human IgG were immobilized on the surface to capture the target antigen——Biotin-labeled Donkey Anti-Human IgG..After the capture,the 300nm magnetic beads（streptavidin labeled） were immobilized on the surface of GMR sensors based on biotin-streptavidin reaction.The variations of resistance of GMR sensors caused by the magnetic beads were detected when a vertical magnetic field of 230 Oe was applied.In this experiment,five kinds of concentration of Donkey Anti-Human IgG were detected,which cause GMR resistance change of 4-164mΩ.A semi-logarithmic relationship is found between them.This kind of array-type GMR chip can be used to quantify certain kind or several kinds of protein in samples simultaneously,which is expected to be used in clinical diagnosis in future.