The invention discloses a light high-strength geopolymer material and a preparation method thereof. The geopolymer material comprises the following components: ground coal gangue powder, regenerated ground powder, superfine metakaolin, silica fume, high-strength gypsum powder, a concrete expansive agent, basalt fibers, steel fibers, water glass, caustic alkali, carboxylic butadiene-styrene latex, a combined foaming agent, a defoaming agent and a water reducing agent. According to the light high-strength geopolymer material provided by the invention, industrial waste residues and old building wastes are effectively utilized; the material has the characteristics of light self weight, high strength, good toughness and the like, has the performances of sound absorption, sound insulation, noise reduction, settlement prevention and the like, and is wide in application range; and the preparation method of the light high-strength geopolymer material provided by the invention is simple in operation steps and does not need high-temperature forming maintenance.