The invention belongs to the novel electrothermal field, in particular to an aqueous nano heating film containing graphene and carbon nanotubes and a preparation method thereof. Comprises a first insulating and flame-retardant flexible film, an aqueous nano three-dimensional conductive layer containing graphene and carbon nanotubes, a copper-silver composite electrode, a temperature-resistant adhesive and a second insulating and flame-retardant flexible film, wherein the heating film has a multilayer film structure, and the thickness of the first insulating and flame-retardant flexible film islarger than that of the second insulating and flame-retardant flexible film. The water-based nano-heating film containing graphene and carbon nanotubes is a new type of nano-heating film. The heat radiation conversion efficiency is up to 70% - 75%, the temperature is homogeneous, the power is basically zero attenuation, the heating temperature can be adjusted from 35 DEG C to 180 DEG C, and the heat resistance and flame resistance of the heating film are improved. The problems of low conversion efficiency of heat radiation, non-uniform heat generation, power attenuation, inability to withstand temperature, heat and flame are eliminated, which prevents the occurrence of safety accidents.