The invention discloses an automobile inner decorative board made of composite materials of natural fibers /
thermoplastic resin, and a mixing method of the composite materials of the
natural fiber / the
thermoplastic resin. The automobile inner decorative board is composed of at least a core layer and a
surface layer. The
surface layer is composed of the following main raw materials, by weight, 5-35 parts of spandex fibers, 25-45 parts of
polyester fibers, 15-25 parts of low-melting-point and
skin-core type composite fibers, and 15-35 parts of high-melting-point hot melting fibers, wherein the difference between the
melting point of the high-melting-point hot melting
fiber and the
melting point of the low-melting-point and
skin-core type composite fibers is larger than 20 DEG C. The core layer is composed of the following main raw materials, by weight, 5-35 parts of
basalt fibers and / or glass fibers, 5-35 parts of the natural
plant fibers with modified surfaces, 15-35 parts of
polyester fibers, 15-25 parts of low-melting-point and
skin-core type composite fibers, and 15-25 parts of high-melting-point fibers. The automobile inner decorative board and the mixing method achieve integration of manufacturing and forming of the composite materials, and the material manufacturing stage can assist the material forming stage directly and effectively.