The invention discloses a sound-insulating noise-reducing fiberboard prepared from vanadium-titanium magnet tailings and a preparation method of the sound-insulating noise-reducing fiberboard. The rawmaterials of the fiberboard include an inorganic material which is composed of vanadium-titanium magnet tailings, silica fume and cement, steel fiber, water and a water reducing agent, and the volumeratio of the steel fiber in the sound-insulating noise-reducing fiberboard prepared from the vanadium-titanium magnet tailings is 0.8-1.7%. The preparation method includes the steps: weighing the rawmaterials at a ratio, performing mixing, performing press molding under a pressure of 10 MPa or above, performing curing at 20-27 DEG C and at a relative humidity greater than 90% for 20-28 hours, and then performing steam-curing at a temperature higher than 75 DEG C for 10-15 hours. The vanadium-titanium magnet tailings is adopted as a raw material, vanadium-titanium magnet tailings aggregate and vanadium-titanium magnet tailings powder which are of different particle sizes are mixed with silica fume, so that energy caused by sonic wave vibration is consumed effectively, the toughness and high-frequency sound-insulation amount of the fiberboard are improved through the steel fiber, and the sound-insulating noise-reducing effects and mechanical properties of the fiberboard are improved.