A three-phase adaptive reclosing scheme using mode current oscillation frequencies is proposed for transmission lines with shunt reactors. Firstly, with phase-mode transformation, the fault boundary conditions are analysed and then the composite mode networks are constructed, respectively, for transient faults and permanent faults. In the composite networks, mode currents of shunt reactors are computed and thus oscillation frequencies are obtained. It is found that in transient fault situations, mode currents oscillate in only one frequency which is the natural frequency of the corresponding mode network. By contrast, the number of frequency components varies in permanent fault situations, depending on the fault type. Based on the frequency characteristics discussed above, a three-phase adaptive reclosing scheme is conceived. In the scheme, the transient fault is identified only if the shunt reactor mode currents contain one frequency which is equal to the natural frequency of the corresponding mode network. Otherwise the fault is taken to be permanent. By simulation, the correctness of the frequency characteristics is verified and the reclosing scheme is validated, hardly affected by fault locations and fault resistance.