The invention discloses insulating paint and belongs to the technical field of paint. The insulating paint is prepared from, by weight, 5-20 parts of nano carbon crystal, 25-40 parts of polyimide, 30-50 parts of epoxy resin, 0.1-1 part of a dispersant, 0.1-2 parts of flatting agent, 0.2-1.0 part of a corrosion inhibitor, 0.1-2 parts of a defoamer and 0.1-3 parts of lysozyme. A preparation method of the insulating paint includes: mixing polyimide with the epoxy resin at 65-80 DEG C; adding nano carbon crystal, the dispersant, the flatting agent, the corrosion inhibitor, the defoamer and lysozyme; stirring. Raw materials are reasonably combined to form the waterborne insulating paint, and the insulating paint has good insulativity, adhesiveness and cohesiveness, a paint film is high in hardness and fullness, the surface of the paint film is uniform, compact, smooth and micropore-free, and the insulating paint has good mechanical performance, wear resistance and scratch resistance.