The invention discloses a flexible super capacitor and a preparing method thereof. The flexible super capacitor comprises electrolyte, a first electrode and a second electrode. The two electrodes are formed by flexible fibrous bases with the surfaces covered by semiconductor materials with pseudo capacitance. One end of the first electrode is of a spiral structure, the second electrode is of a linear structure, and the second electrode is arranged in the spiral structure of the first electrode. The electrolyte wraps the spiral structure of the first electrode and the part, located in the spiral structure of the first electrode, of the second electrode, and the two electrodes are fully combined. The flexible super capacitor effectively solves the problems that an existing capacitor is low in specific energy, in the conventional preparing technology, combination of the semiconductor material with pseudo capacitance and the flexible fibrous base is not firm, the semiconductor material and the flexible fibrous base grow in a disorderly mode, internal resistance is high, and an electronic transmission route is long, and the volumetric specific volume and volumetric specific energy of the capacitor are greatly improved.