The invention discloses resin-spray-adhesive mica paper and a preparing method thereof. The mica paper comprises multiple layers of mica paper bodies with pulp sheets of different grain diameters, thesurface of the inner-side fine-pulp-sheet mica paper body is subjected to rough treatment and hole forming treatment, then a fiber reinforced layer is formed in an interlayer, and is subjected to hot-pressing treatment to be dried, then a resin spray-adhesive layer is sprayed to the surfaces of multiple layers of the fine-pulp-sheet mica paper after hot-pressing treatment, a layer of rough-pulp-sheet mica paper body is covered again, then secondary hot-pressing treatment is conducted, and then the resin-spray-adhesive mica paper is obtained. By means of the resin-spray-adhesive mica paper andthe preparing method thereof, the problem that the strength of the mica paper is low can be effectively solved, the electrical insulating property and the tensile strength are considered at the sametime, and the advantages of being resistant to breakdown, high in insulation, capable of insulating heat and the like of natural mica are kept. In addition, the invention discloses a resin spray adhesive for preparing the mica paper, the resin spray adhesive can be applied to the technology for preparing the resin-spray-adhesive mica paper, and the dielectric strength and the mechanical strength of the resin-spray-adhesive mica paper are effectively improved.