The invention discloses a raw material formula used when an automobile thermal insulating layer is manufactured. Raw materials comprise epoxypropane condensation compounds, flame retardants, foaming agents, pigments, methylene chloride, ammonia, tin and toluene diisocyanate. The raw material formula is reasonable, and a produced thermal insulating layer backing material has the advantages of being good in sound-insulating effect and thermal-insulating effect, low in VOC content and excellent in performance.