In order to make the stator punching sheets have correct location, reliably pre-tightening and demould smoothly in the mold, using the way of two pins on one face，the irregular situation among the stator sheets and the perpendicularity error were relieved when the sheets were clamped and located. By small inclination wedge, the tightness of sheets was insured. By the axial limiting displacement，the end face of stator core was prevented from butterfly shape when it was put into the stent. By HAFU plywood, the demoulding problem was settled successfully when the stent sleeve was jammed. Volume production has shown that the folding mould has merits of simple structure，accurate and reliable location，safe and easy control，cheap cost and stable quality.