The invention relates to the technical field of an inductance-adjustable resonant reactor, in particular to a bidirectional adjustment mechanism for an open iron core of an inductance-adjustable resonant reactor. The bidirectional adjustment mechanism comprises a base and a reactor outer cylinder, wherein the base and the reactor outer cylinder are fixedly connected by bolts, a motor is arranged in the base, a motor output shaft is connected with a lower screw rod via a transmission mechanism, a lower transmission sleeve is in threaded connection with an outer side of the lower screw rod, a low iron core sleeves the lower transmission sleeve, an upper end of the lower screw rod is connected with a transmission shaft, an upper end of the transmission shaft is connected with an upper screw rod via a connector, the thread rotation directions of the upper screw rod and the lower screw rod are opposite, an upper transmission sleeve is in threaded connection with an outer side of the upper screw rod, an upper iron core sleeves the upper transmission sleeve, connection cylinders sleeve outer sides of the lower iron core and the upper iron core, and an upper line pack and a lower line pack are respectively and fixedly arranged at outer sides of the upper connection cylinder and the lower connection cylinder. By designing same range of the inductance-adjustable resonant reactor and change with different adjustment rates, the inductance adjustment range is expanded, the inductance adjustment rate is improved, and insulation processing of the iron core and coil voltage distribution is improved.