The invention discloses a low-voltage power grid three-phase imbalance adjustment method based on a phase-change switch. A difference between average current and the inter-phase maximum current is calculated, an average current fixed value and an inter-phase maximum current fixed value for starting imbalance adjustment is calculated according to transformer capacity and a load rate, three-phase transfer load is calculated, a load transfer direction is determined, the phase actually needs to transfer load out if the load which needs to be transferred is positive, the phase actually needs to receive load if the load which needs to be transferred is negative or zero, a phase-change switch which needs load transfer and a transferred target phase are determined according to the phase and the actual load of each phase-change switch, a phase-change switch action queue is generated, the phase-change switches are sequentially controlled to perform load transfer until all phase-change switches complete load transfer, and the system thus achieves the best balance state in the current condition. The method is used for low-voltage power grid three-phase imbalance treatment, the three-phase imbalance degree is reduced, voltage drop is reduced, power supply voltage treatment is improved, and line loss is reduced.