The present invention discloses a sound-absorbing piece and a preparation method thereof. The preparation method of the sound-absorbing piece comprises: preparing perforated sound-absorbing cotton matched with a preset cavity in shape; mixing sound-absorbing material powder with a solvent and a template agent to prepare a sound-absorbing slurry; impregnating the perforated sound-absorbing cotton with the sound-absorbing slurry for a preset period; and drying the perforated sound-absorbing cotton impregnated with the sound-absorbing slurry to remove a liquid in the perforated sound-absorbing cotton.