Abstract: The slag powder, fly ash and desulfurized gypsum as ternary cementitious materials were selected to replace part of the cement, and the polystyrene particles and foam were added to prepare wall materials, and the PP and PVA fibers with a length of 12 mm were incorporated to conduct the tests of 7, 28 d cube compressive strength and flexural strength. The influences of the two fiber content on the compressive strength and flexural strength of wall materials were analyzed, and the mechanical properties of wall materials of the optimal fiber ratio were studied. The results show that the appropriate amount of PP and PVA fibers can improve the 7, 28 d cube compressive strength and flexural strength of wall materials, and they increase first and then decreases with the increase of fiber content. When the volume fractions of two fibers are 0.9% and 1.2% respectively, the 7, 28 d cube compressive strength and flexural strength of wall materials are the largest, and the volume fraction of PVA fiber with 1.2% is the preferred ratio. Compared with the wall material without fiber, the thermal conductivity of the wall materials with the preferred ratio increases by about 2.6%, and the water absorption, strength loss rate and mass loss rate are reduced by 6.0%, 5.0% and 8.7% respectively, and the axial compressive strength, elastic modulus and splitting tensile strength are increased by 4.7%, 3.0% and 13.9% respectively.