A device for equalizing voltage of a battery pack comprising: a plurality of serially-connected batteries, wherein each battery has a positive electrode and a negative electrode; a sampling unit coupled to the battery pack for sampling the voltage signals of batteries of the battery pack; an analog-to-digital converting unit coupled to the sampling unit for converting the sampled voltage signals into digital voltage signals; a control unit coupled to the analog-to-digital converting unit for generating a sampling control signal to control the sampling unit and driving signals based on digital voltage signals; an equalization unit for generating an equalization signals for equalizing batteries of the battery pack based on the driving signal; and a filter unit coupled to the equalization unit for applying the equalization signals to batteries of the battery pack, characterized in that the sampling unit includes a multiplex signal gating circuit and a plurality of voltage divider circuits coupled to the multiplex signal gating circuit, wherein each voltage divider circuit includes an output terminal; and the multiplex signal gating circuit includes a control terminal, an output terminal and a plurality of input terminals; the control unit is coupled to the control terminal of the multiplex signal gating circuit to control the signal gating; the plurality of input terminals of the multiplex signal gating circuit are connected to the output terminals of the plurality of voltage divider circuits, respectively; and the output terminal of the multiplex signal gating circuit outputs the sampled voltage signals to the analog-to-digital converting unit. a plurality of serially-connected batteries, wherein each battery has a positive electrode and a negative electrode; a sampling unit coupled to the battery pack for sampling the voltage signals of batteries of the battery pack; an analog-to-digital converting unit coupled to the sampling unit for converting the sampled voltage signals into digital voltage signals; a control unit coupled to the analog-to-digital converting unit for generating a sampling control signal to control the sampling unit and driving signals based on digital voltage signals; an equalization unit for generating an equalization signals for equalizing batteries of the battery pack based on the driving signal; and a filter unit coupled to the equalization unit for applying the equalization signals to batteries of the battery pack, characterized in that the sampling unit includes a multiplex signal gating circuit and a plurality of voltage divider circuits coupled to the multiplex signal gating circuit, wherein each voltage divider circuit includes an output terminal; and the multiplex signal gating circuit includes a control terminal, an output terminal and a plurality of input terminals; the control unit is coupled to the control terminal of the multiplex signal gating circuit to control the signal gating; the plurality of input terminals of the multiplex signal gating circuit are connected to the output terminals of the plurality of voltage divider circuits, respectively; and the output terminal of the multiplex signal gating circuit outputs the sampled voltage signals to the analog-to-digital converting unit.