A trench gate structure and a manufacturing method therefor. The trench structure comprises a substrate (10), a trench on the surface of the substrate (10), an insulating spacer (20) on the substrate (10), a gate oxide layer (41) on the inner surface of the trench, and a polysilicon gate (40) on the gate oxide layer (41). The insulating spacer (20) abuts against the trench by means of a slope structure (21) of the insulating spacer; the polysilicon gate (40) extends onto the insulating spacer (20) along the slope structure (21) in the trench; the insulating spacer (20) comprises a polysilicon gate pull-up area (22) that is concave downwards with respect to other parts of the insulating spacer (20); the polysilicon gate (40) extending out of the trench is rested on the polysilicon gate pull-up area (22).