The invention provides a miniature ultra-wide-band antenna. The miniature ultra-wide-band antenna comprises a dielectric substrate and metal patches on the upper surface and the lower surface of the dielectric substrate, wherein the metal patch on the upper surface is an antenna patch, and the metal path on the lower surface is a microstrip feeder; the antenna patch comprises an earth plate, a short branch knot and a long branch knot, each of the long branch shot and the short branch shot comprises an internal slot line and an external slot line, the center of the earth plate is provided with a vertically slotted slot line, the upper part of the slotted line is connected to the internal slot line of the long branch knot, the bottom of the slotted line is connected to a circular slot, the edge shapes of the external slotted lines and the internal slotted lines of the long branch knot and the short branch knot adopt exponential type transition curves, and an exponential annular slot is formed between an external slot of the long branch knot and an internal slot of the short branch knot. The overall space of the miniature ultra-wide-band antenna is compact in structure, an antenna backboard is tightly connected with the feeder, a radiation element saves the dimensions while meeting a phase-position requirement in virtue of a coplanar strip line coupling power supply manner, the design is convenient, the principle that the antenna is additionally provided with the exponential annular slot to transfer the radiation of low-frequency points is easy to understand, and the replicability of a miniature scheme is high.