The reactor coil adopts a dry hollow structure consisting of coaxial, concentric, multi-layer and wound wires, and a epoxy resin impregnated glass fiber envelope. After curing, the glass fiber steel self-sealing body is formed, avoiding oil immersion. The reactor has the disadvantages of oil leakage and flammability. The inductance value should not change due to changes in current, and the linear and sexual properties are good. At the same time, the multi-strand small-section conductors that are wound together can reduce Eddy current loss and improve the quality factor.