A step-varying equalization method, a device, a medium, a battery pack, and a vehicle are provided. The method includes: initiating coarse-tuning equalization for a cell in the series-connected battery when an initial equalization difference of the cell reaches a preset coarse-tuning requirement; determining a first state of charge (SOC) equalization difference according to a first voltage value of the cell after completion of the coarse-tuning equalization when a first real equalization difference of the cell after the coarse-tuning equalization reaches a preset fine-tuning requirement, and initiating fine-tuning equalization for the cell with a first equalization step size based on the first SOC equalization difference; and determining that SOC equalization of the cell is completed when a second real equalization difference of the cell after completion of the fine-tuning equalization is less than or equal to a target equalization value.