Magnetic materials are generally strong magnetic substance, it is old and widely used functionality materials, the magnetism of material was known and used 3000 years ago, for example natural magnets used as a compass in ancient China. Modern magnetic materials already widely used in our life, for example, permanent magnets were used in motors. Magnetic materials have a close relationship with automation,mechanical-electrical integration etc. According to demagnetized easily or not, there are two families, one is a soft magnetic material which easily demagnetized, the other one is a hard magnetic material which is difficult to be demagnetized, which also called permanent magnet material.The remanence of soft magnetic material is lower, while remanence of hard magnetic material is higher.