The invention discloses a forming method and a cup body structure of a paper cup. The forming method adopts the forming steps of selecting raw material paper wood, carrying out type setting and die cutting and forming the paper cup, wherein in the step of carrying out type setting and die cutting, a sector cup body cutter die is adopted to carry out die cutting on the raw material paper wood to form sector cup body paper wood in a type setting and material drawing manner of forming an included angle within an angle range of 5 degrees to 45 degrees between the center line of the cup body cutter die and the extension direction of fibers on an outer paper layer; then the sector cup body paper wood is folded in a surrounding manner to be adhered to form a cup body of the paper cup. The forming method can have high flexibility and variability in the type setting and die cutting process by utilizing a manner of changing the included angle, moreover, can simultaneously consider the structural intensity and the durability of the cup body and a cup mouth and has high industrial utilization value.