The invention discloses a screw plastic helical gear die. A static model core under a channel beset part on the bottom of a stripper plate, a helical gear cavity and an active model cavity are successively sleeved on the center of a static model cavity plate up and down. A screw embedding part is successively inserted in an active template, an active die bottom plate and the center of an active model cavity plate through a screw base. The end part of the screw embedding part stretches into the active model cavity, the helical gear cavity and the blind hole of the static model cavity. A slider which is arranged under the active model cavity is arranged on the periphery of the screw embedding part through two dimidiate round shapes. The helical gear cavity, the plastic helical cavity body on the center of the active model cavity and a large sleeve cavity body are communicated with a flow channel. The end part of the screw embedding part, the helical gear and parts of the large sleeve of the invention are provided with high positioning precision without mutual interference. Thus, the concentricity of finished products is high. The requirement for producing screw helical gear products with high precision can be satisfied without special devices. And formed products can be fetched out without restriction just through movable sliders and the backspace of curved pins and cam drivers.