The invention relates to the technical field of reactors, in particular to a coil winding device of an air-core reactor, comprising a support, a laterally moving mechanism, a longitudinally moving mechanism, a rotating mechanism, a lifting mechanism and a winding mechanism, wherein the laterally moving mechanism is arranged at the upper part of the longitudinal support and comprises a laterally moving vehicle, the rotating mechanism comprises a rotating disk, a rotating motor and two arc-shaped moving plates, the output end of the lifting mechanism is connected with a lifting plate, the winding mechanism is fixed at the bottom of the lifting plate, and the wire winding mechanism comprises a wire winding machine, a counterweight block, a left winding arm, a right winding arm, a left air cylinder and a right air cylinder. Compared with the prior art, the coil winding device subverts the traditional reactor wire winding method, the whole process efficiency is very high, and the problem that operation on a large-tonnage reactor is inconvenient at present is solved.