The construction sector has become the most critical source of carbon emissions, but the existing thermal insulation materials such as thermal insulation mortar have obvious limitations, so it is urgent to develop building thermal insulation materials with superior performance and low cost. Aiming at the problem of poor bond strength of foam thermal insulation mortar, this research team selected basalt fiber as admixture to verify the influence of basalt fiber content on its performance and the economic feasibility of thermal insulation mortar. The main finding is that basalt fiber as an additive can obviously improve the crack resistance of thermal insulation mortar. When the content of basalt fiber increases from 0 to 2.5%, the compressive strength of mortar increases at first and then decreases, and the bond strength increases nonlinearly, but the thermal conductivity and dry density also increase. Therefore, the optimal content of basalt fiber is 1.5%. The improvement effect of fire resistance of thermal insulation mortar with 1.5% basalt fiber content is better. After curing for 28 days, the mass loss rate of the sample is reduced by about 11.1% after high temperature, and the relative compressive strength is increased by about 9.71% after high temperature. The raw material cost of the new fireproof thermal insulation mortar improved by basalt fiber is lower, and the cost of the finished product is reduced by 16.98%, 28.18%, 33.05% and 38.96%, respectively, compared with the four types of thermal insulation mortar already used in the market. More importantly, the economic recovery period of the new fireproof and thermal insulation mortar is undoubtedly shorter than that of alternative thermal insulation or energy storage materials, which not only achieves low emission and environmental protection, but also satisfies the economic feasibility.