The invention provides a device for nondestructively dismantling a motor stator winding and a stator winding dismantling method. The device comprises: a support base; a first iron core positioning device used for positioning one end or both ends of the stator iron core with a yoke portion positioned at the outer side; a second iron core positioning device used for positioning one end or both endsof the stator iron core with a yoke portion positioned at the inner side; a shearing device; a lead screw, a thread block and a first support, wherein the first support is rotationally installed at the support base round the axis of the stator iron core, the thread block is installed at the first support and is rotated to the front side of each stator slot with the first support, the lead screw isinstalled at the thread block, the rear end of the lead screw is connected with one or more than one conductors at the middle portion of the wire cluster in each stator slot to move forwards while rotation to allow the conductor to rotate and pull the conductor out of the wire cluster; a loosening device; a winding pull-out device having a first hydraulic rod and a connection device connected with the extending end of the first hydraulic rod and the winding on the stator iron core to pull out the winding on the stator iron core.