The invention discloses an assembly method for a novel sound-insulation thermal-insulation material of a passenger car. The method comprises measuring and cutting, bonding position cleaning, gluing, sound-insulation board assembly, thermal-insulation noise-reduction cotton assembly and repair processing. A sound-insulation board EVA made of the novel material and thermal-insulation noise-reduction cotton F800FR HT are used together in a matching way and then sealed by dedicated adhesive tape PUR-01, the sound-insulation board EVA has sound-insulation property and inflaming retarding characteristics, is odourless at the high temperature, easy to clip and cut, convenient to install and good in extensibility performance, and does not generate particles or contaminate other materials; high-standard environmental protection requirements are met; the technological process is simple, the scrap material and excess stock wastage are small, the sound-insulation effect of the passenger car is improved after assembly, and no peculiar smell is generated.