The invention relates to a sector-shaped curtain bottom piece telescopic positioning device. By means of the positioning device, it can be guaranteed that a curtain is kept stiff when flat unfolded, the curtain can be automatically and orderly folded into a sector shape when a drawstring is pulled, the service life of the curtain can be remarkably prolonged, and the positioning device further has the advantages of being simple in structure and low in cost. According to the technical scheme, the sector-shaped curtain bottom piece telescopic positioning device is characterized by comprising a hinge base fixed to the center of a sector-shaped curtain bottom piece and connected with the drawstring of the curtain, two hinge arms rotationally and symmetrically hinged to the hinge base, and two sliding sleeves distributed on the two sides of the hinge base respectively and connected with the hinge arms in an inserted mode and matched with the hinge arms in a sliding mode one to one. The rotation axes of the two hinge arms are horizontal and perpendicular to a wall. The rotation angle of each hinge arm at least includes the depression angle range from the horizontal line to the vertical line.