The invention discloses phosphate cement foam concrete and a preparation method thereof. The phosphate cement foam concrete is prepared from, by mass, 200-400 parts of phosphate cement, 20-80 parts ofmineral admixture, 5-20 parts of foamer, 0.5-1 part of foam stabilizer, 4-10 parts of catalyst and 30-100 parts of water, wherein the foamer is hydrogen peroxide. The preparation method includes thesteps that the phosphate cement, the mineral admixture, the foam stabilizer and the catalyst are evenly mixed; then, the water is added for primary stirring, and the hydrogen peroxide is added for secondary stirring; finally, pouring, forming and curing are carried out to obtain the phosphate cement foam concrete. The prepared foam concrete is high in strength, the compression strength of foam concrete with the volume weight of 1000 kg/m<3> in 28 days is higher than 20 MPa, and the compression strength of foam concrete with the volume weight of 500 kg/m<3> in 28 days is higher than 6 MPa; thepore structure of the foam concrete is fine, and the average size is smaller than 0.5 mm.