A nano-patterned system comprises a vacuum chamber, a sample stage and a magnetic-field applying device. The magnetic-field applying device comprises a power supply, magnetic poles, and a magnetic-field generation device having a magnetic conductive soft iron core and a coil connected to the power supply and wound on the soft iron core to generate a magnetic field. The soft iron core is a semi-closed frame structure and the magnetic poles are respectively disposed at the two ends of the semi-closed frame structure. The sample stage is inside the vacuum chamber. The magnetic poles are opposite one another inside the vacuum chamber with respect to the sample stage. The coil and soft iron core are outside the vacuum chamber. The soft iron core leads the magnetic field generated by the coil into the vacuum chamber. The magnetic poles locate a sample on the sample stage and apply a local magnetic field.