The feasibility of bilaterally-fed AC traction power supply system is up to the balanced current. A method was proposed in this paper to predict the balanced current i.e., measuring the voltages of the traction power networks on both sides in the section post, and then dividing the no-load voltage difference by the total system impedance that was referred to the traction networks. Firstly, the power supply schemes of trolley-rail & negative-feeder (TRNF) and auto-transformer were studied. Secondly, the balanced current prediction method was verified with the IEEE 14-bus test system. Finally, the feasibility of bilaterally-fed power supply scheme on the Batuta-Jungar railway was discussed. The test shows that the errors of the balanced current are approximately equivalent to the no-load current of the traction network, so the proposed method can be used in the studies of bilaterally-fed and continuous co-phase power supply schemes.