The invention provides a graphene modified foamed plaster sound-absorbing material, which is prepared based on an industrial byproduct plaster and has better strength, toughness and sound-absorbing characteristic and high additional value. Noise pollution becomes a main environment problem complained by urban residents and sound absorption is one of important measures for improving indoor sound quality and controlling noises. An existing traditional sound-absorbing material wastes a lot of raw materials and the requirements on low-carbon materials cannot be met. The graphene modified foamed plaster sound-absorbing material is prepared from the following raw material: the industrial byproduct plaster, a retarder, water, a foaming agent, a catalyst, a foam stabilizer and graphene oxide. Thesound-absorbing material is modified through the graphene so that the additional value of the material is improved; a high-value utilization technology is provided for the material and the graphene modified foamed plaster sound-absorbing material also has the characteristics that wastes are changed into valuable things and greenness and low carbon are realized, so that industrial application in the future is expanded.