Sepiolite, a natural nano-material, was chosen as a carrier to prepare supported nanoscale zero-valent iron (nZVI). The effects of preparation conditions, including mass ratio of nZVI and activated sepiolite and preparation pH value, on properties of the supported nZVI were investigated. The results showed that the optimal mass ratio of nZVI and sepiolite was 1.12:1 and the optimal pH value was 7. The supported nZVI was characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and energy dispersive spectrometer (EDS), and furthermore an analogy model of the supported nZVI was set up. Compared with the nZVI itself, the supported nZVI was more stable in air and possessed better water dispersibility, which were beneficial for the degradation of bromamine acid aqueous solution. The degradation characteristics, such as effects of supported nZVI dosage, initial concentration and initial pH value of the solution on the decolorization efficiency were also investigated. The results showed that in an acidic environment the supported nZVI with a dosage of 2 g/L showed high activity in the degradation of bromamine acid with an initial concentration of 1,000 mg/L, and the degree of decolorization could reach up to 98%.