The invention discloses a geopolymer/waste rubber powder composite material and a preparation method thereof. The geopolymer/waste rubber powder composite material comprises the following raw material components in parts by weight: 35-70 parts of geopolymer alkali activated material and 30-65 parts of waste rubber powder/modified water glass mixed slurry; the waste rubber powder/modified water glass mixed slurry is prepared from the following components in parts by mass: 5-50 parts of waste rubber powder and 50-95 parts of modified water glass. The prepared composite material adopts cast molding; and after the composite material is cured, the compressive strength is between 15MPa and 96MPa, and the elasticity modulus is between 92MPa and 400MPa. The composite material disclosed by the invention not only solves the problem of utilization of waste rubber, but also solves the technical problems of high brittleness and insufficient toughness of geopolymer materials. The composite material can be applied in the engineering fields of buildings, traffic, military affairs and the like.