The invention discloses a compensating reactor and relates to the technical field of power transmission and distribution, in particular to the structure of an electric reactor. The compensating reactor comprises a reactor body, wherein the reactor body comprises an upper iron core pillar, a lower iron core pillar, an iron core yoke pillar and an iron core iron yoke, and a plurality of iron discuses are arranged between the upper iron core pillar and the lower iron core pillar from bottom to top in sequence. According to the compensating reactor, a structure of one-phase one-pillar is adopted, sleeved installation is simple, margin is large, and worker operation is convenient to do. The type of the structure is further capable of effectively reducing flux leakage and reducing loss.