Preparation method of ultra-light sandwich structure composite material

Disclosed is a preparation method of an ultra-light sandwich structure composite material. The method comprises the steps that a hot melting prepreg material is prepared; then, the prepared hot melting prepreg material is laid according to the preset paving direction and paving layers, and a laminate preform body is obtained; then, the surface of a curved metal mold is paved with metal barrier strips, the metal barrier strips and a metal mold are fixedly connected mechanically, and then, the laminate preform body is laid on the side face flanges of the barrier strips; then, a coating for an opening honeycomb with the density being 30-50 kg/m coats the surface of the laminate preform body, and then the honeycomb is paved with the hot melting prepreg material; finally, the preform body is sealed by adopting a silicone rubber sealing strip, curing is performed for 2 h under the temperature of 130 DEG C, and the ultra-light sandwich structure composite material is obtained. According to the method, the weight of the product is lowered, the problem that the honeycomb on the side face is exposed is solved; meanwhile, the skin can be effectively prevented from warping, and the phenomenon that honeycomb cores in a local area are sunken is avoided.