This invention relates to a circular magnetic multi-layer membrane, which characterized with: the cross section of the said magnetic multi-layer membrane takes on the closed circle shape, the circle's inner diameter being 10~100000nm, outer diameter being 20~200000nm. In accordance with the classification of the forming materials, the magnetic multi-layer membrane of the invention includes the circular magnetic multi-layer membrane without pinning and the circular magnetic multi-layer membrane with pinning, and it can be prepared through micro-processing method or insulator micron, submicron or nano-particles masking method. The circular magnetic multi-layer membrane of the invention has no fading magnetic field, weak shape anisotropy, and it can be widely used in various devices with the core of magnetic multi-layer membrane, such as magnetic random access memory, computer magnetic heads, magnetic-sensing sensors, etc.