Using recycled waste polyvinyl chloride (PVC) pipe powder as a raw material, the chain extension modification was carried out by triallyl isocyanurate (TAIC), and SiO₂ hollow microspheres modified by silane coupling agent KH-550 were added to prepare PVC board with sound insulation and heat insulation function, so as to realize the recycling of waste PVC material. The results show that TAIC can effectively increase the viscosity of PVC melt and improve the mechanical properties of PVC board by enlarging the molecular chain length of PVC. Modified SiO₂ microspheres can enhance the stiffness of PVC, thus improving the mechanical properties of PVC board. Modified SiO₂ microbeads can improve the hydrophobicity, sound insulation, and heat insulation performance of PVC board. When the content of modified SiO₂ microspheres is 3 phr, the thermal conductivity of PVC board decreases from 0.35 W/(m·K) to 0.14 W/(m·K). When the content of modified SiO₂ microspheres is 15 phr, the maximum acoustic wave barrier ratio of PVC board is increased from about 50% to about 97% in the range of 800~1 400 Hz.