The present invention relates to a negative pressure wound therapy device, system and method. The negative pressure wound therapy device is connected with a dressing, and comprises a housing, a control circuit board, a pump, and an aspiration conduit. The pump generates negative pressure. The pump may comprise a voltage-actuated deformation element (such as piezoelectric vibration element) to push fluid from an aspiration end to a discharge end. The aspiration conduit has a pump end and a dressing end. The pump end is fluidly connected to the aspiration end of the pump, and the dressing end is fluidly connected to the dressing used for covering a wound. The control circuit board is disposed in the housing, controls the pump to generate the negative pressure in the aspiration conduit, and applies negative pressure to the wound covered by the dressing via the aspiration conduit.