The invention provides a preparation method for a nanoscale heat conducting adhesive tape. The method comprises the following steps: (1) preparing high-temperature resistant polyacrylic acid adhesive; (2) mixing the high-temperature resistant polyacrylic acid adhesive with alpha-Al2O3 by the weight ratio of (20-30): (30-45), and then implementing the mulling to obtain a first semi-finished product; (3) mixing the first semi-finished product with Al(OH)3 by the weight ratio of (50-75): (30-45), and then implementing the mulling to obtain a second semi-finished product; (4) placing the second semi-finished product and polyester fabric or glass fiber in high-temperature pressure piece conveying equipment, adding platinum catalyst reaction agent in the equipment, and implementing the addition reaction by a high-temperature oven to form the inseparable and integrally formed heat conducting adhesive tape, wherein the weight of the platinum catalyst reaction agent is 1-5% of that of the second semi-finished product. The method achieves a loading level of more than 92% by using the mulling of nanoscale aluminum oxide and aluminum hydroxide and the closest crystal packing, and enables the material characteristics to achieve the results that the thermal conductivity is 3.5 W/mK, the viscosity achieves 2.0 Kgf/25 mm, the volume resistance is above 1012, and the flame resistance meets the international standard of UL94V-0.