The invention discloses a method for manufacturing a dual-layer polysilicon gate. The method includes: depositing silicon nitride on silicon oxide of an integrated circuit to be processed; performing anisotropic etching on the silicon nitride to form sidewalls of silicon nitride on sidewalls of a first layer of polysilicon gate of the integrated circuit to be processed; manufacturing a second layer of polysilicon gate; and rinsing the sidewalls of silicon nitride.