Provided are a barcode nano-wire for decoding a hard magnetic segment by using highly sensitive magnetic sensors and a bio-sensing system using the barcode nano-wire. Integration of hard magnetic and non-magnetic segments produces the barcode nanowire and magnetic segments are detected using highly sensitive magnetoresistance sensors. The non-magnetic segment uses a non-magnetic material and a specific biomolecule for bioanalysis is immobilized at a specific portion of the barcode nano-wire. The hard magnetic material has an advantage of higher coercivity and high remanence magnetization, which is considered as an important parameter in selecting the material. The hard magnetic segments produce distinguishable strong stray fields for individually detecting segments using conventional magnetic sensors for multiplexed bioanalysis.