The utility model discloses a can mould plastics and take injection mold of arc hole part, including front mould, back mould, the front mould is equipped with front mould mounting panel, preceding framed at least, preceding framed built -in two sliders that have, and the front mould mounting panel links firmly two drive blocks that the slider moved in opposite directions of drive, and two slider looks laterads respectively are equipped with the shaping die cavity that forming groove constitutes injection molding parts, back mould is equipped with back mould mounting panel at least, back die holder, back die holder pin joint has firstly, the second pivot, first pivot links firmly a driven gear and first driving gear, the second pivot links firmly the 2nd driven gear, first driving gear and the 2nd driven gear mesh mutually, the hydro -cylinder still is equipped with on the back die holder, rack and sector gear, the rack is driven by the hydro -cylinder, the rack meshes with a driven gear mutually, sector gear and the 2nd driven gear mesh mutually, sector gear one side links firmly and has the first mold core axle of segmental arc, the segmental arc of first mold core axle stretches into during the compound die the shaping die cavity. This mould operating efficiency, yield are higher.