The invention discloses a flame-retardant aluminum-nickel alloy material and a preparation method thereof, and belongs to the field of alloy materials. The method comprises the following steps: step 1, feeding ammonium thiosulfate, acetic tin, stannous octoate, a titanate coupling agent, calcium peroxide, carbon powder, nickel powder, aluminum powder, calcium oxide and phosphorous acid into a high-speed mixer to thermally mix for 20 to 30 minutes under the controlled temperature of 100 to 120 DEG C; step 2, transferring into a low-speed mixture to coldly mix; adding aluminum hydroxide, calcium hydroxide and hydroxymethyl cellulose, wherein the temperature is controlled to be 40 to 50 DEG C, and the cold mixing is performed for 30 minutes; and step 3, extruding and pelleting, and then cooling. The flame-retardant aluminum-nickel alloy material is high in fireproofing and flame retardant performances; the apparent porosity is about 40%; the volume weight is low; the fireproofing grade is high; the flame-retardant aluminum-nickel alloy material is a lightweight fireproof material; hydroxymethyl cellulose is added, so that the volume weight of the material can be reduced, and the mass is reduced; stannous octoate can improve the fireproofing performance.