Potassium feldspar and fly ash cenosphere (FAC) were used as raw materials, and bauxite was used as a texturizer for the preparation of lightweight insulation materials at 900~1 150 ℃ for 1 h in the air atmosphere. The influence law and action mechanism of sintering temperature and bauxite content on the service performance of lightweight insulation materials were studied. The results show that the cold physical properties of lightweight insulation materials are effectively optimized by the increase of sintering temperature or bauxite content. The sample containing 20% (mass fraction) bauxite has the best physical properties after sintering at 1 100 ℃. The bulk density, true porosity, and cold crush strength of sample are (0.97±0.01) g·cm-3, (63.7±0.5)%, and (9.42±0.21) MPa, respectively. Besides, the sample has good thermal insulation performance with thermal conductivity of 0.147 W/(m·K) at 300 ℃ and thermal conductivity of 0.229 W/(m·K) at 600 ℃. Compared with general lightweight insulation materials, the porous potassium feldspar-FAC lightweight insulation material has excellent service performance and lower preparation cost.