The present invention relates to a method of preparing an aerogel blanket in which, a surface of a base material for a blanket is activated and roughness and porosity of the surface of the base material for a blanket are increased to increase adhesion performance of a silica aerogel by inducing etching of a surface of a base material for a blanket using an acidic solution, and mechanical flexibility is increased and the generation of dust is minimized by further performing a gel deformation process of introducing cracks into the aerogel, and a low-dust and high-insulation aerogel blanket prepared according to the present invention.