The invention provides a superconducting magnet applying high-temperature-forming insulation material and a preparation method thereof. The insulation material is prepared from, by weight, 25%-45% of a liquid polymer, 40%-70% of glass fiber fabric and 0.5%-50% of a functional filler, the liquid polymer refers to a liquid silicon-based polymer and a modified polymer thereof, the glass fiber fabric is of high-temperature glass fiber fabric, and the functional filler is a composition of one or multiple of silicon carbide, silicon nitride, silicon oxide, aluminum oxide, aluminum powder, silicon nanoparticles or crystal whiskers. The insulation material is simple in preparation method, suitable for high temperature forming and good in process operation, and the problem that a traditional magnet applying epoxy resin insulation material cannot be formed in high temperature is solved; the prepared insulation material is remarkable in anti-radiation property, cryogenic mechanical property and insulation property.