The present invention is a polyimide varnish for conductor coating, which provides a polyimide varnish comprising: a polyamic acid solution prepared through polymerization of at least one dianhydride monomer and at least one diamine monomer in an organic solvent; an aromatic carboxylic acid having four or more carboxyl groups; an alkoxy silane coupling agent; and an antioxidant, wherein the polyimide varnish has a solid content of 15 to 38 wt % on the basis of the total weight thereof, and a viscosity at 23° C. of 500 to 9,000 cP, and the coated material prepared from the polyimide varnish has a degree of softening resistance of 520° C. or higher, and a breakdown voltage (BDV) of 8 kV/mm or higher.