The invention provides a method to fashion an inverted trapezoid-shaped polysilicon section, relating to semiconductor manufacturing technique. Conventional dry etching methods fail to produce inverted trapezoid-shaped polysilicon sections which are identical in shape with even feature linewidth. The method of the invention includes the following steps: firstly, a base plate is provided and a gate oxide layer is developed on the base plate; then a plurality of polysilicon layers are deposited sequentially on the gate oxide layer and the polysilicon layers gradually decrease in doping concentration; after that, the polysilicon layers are processed with dry etching so that vertical sections can be developed on the the polysilicon layers; the polysilicon layers are processed with wet etching so that inverted trapezoid-shaped sections can be developed on the polysilicon layers. The method of the invention can produce an inverted trapezoid-shaped polysilicon section with the upper part wide and the lower part narrow and can ensure even feature linewidth.