Abstract: The discovery of giant magnetoresistance effect (GMR) is not only very important in science, but ignites the technical innovation of the magnetic storage. It is the first time that the spin degree of freedon was widespread use in everbody's life.The new field of spintonics which studies the spin properties of all kinds of material after the discovery of GMR was opened.

Key words: giant magnetoresistance, tunneling magnetorsistance,spintronics