The utility model discloses a lithium ion battery equalizing circuit which is arranged among N batteries connected in series. The lithium ion battery equalizing circuit comprises N MOS (metal oxide semiconductor) tubes, N energy-storing inductors, N filter capacitors, N freewheel diodes and MOS tube control circuits, wherein N is larger than or equal to 2; one of the filter capacitors is connected with one battery in parallel; one of the MOS tubes is connected with one energy-storing inductor in series and then connected at two ends of the battery; one ends of the freewheel diodes are connected with the energy-storing inductor, and the other ends are connected with total normal or total load of the battery; and the MOS tube control circuits are respectively connected with the N MOS tubes so as to control the switch on and off of each MOS tube. In the utility model, simple circuit elements can be utilized; voltage equilibrium of batteries connected in series of the battery pack can be realized; and electric quantity of the battery with higher voltage can be directly transferred to the battery with lower voltage under any state, thus realizing rapid equilibrium of the batteries.