The invention relates to a preparation method for a snake bone device of an endoscope. The snake bone device comprises a snake bone front pitch circle, a snake bone rear pitch circle, connecting pin rolls and a plurality of snake bone middle pitch circles connected between the front pitch circle and the rear pitch circle. The preparation method sequentially comprises the following specific preparation steps: selecting materials; cutting, leveling and polishing the snake bone front pitch circle, the snake bone middle pitch circles and the snake bone rear pitch circle; during shape cutting of the snake bone middle pitch circles and the snake bone rear pitch circle, respectively cutting out a clamping opening which is communicated with a connecting shaft hole, and the corresponding connecting shaft hole; processing and forming the connecting pin rolls by stainless steel wires on a lathe according to drawing requirements; stamping wire penetrating slot openings of the snake bone front pitch circle and the snake bone middle pitch circles by utilizing a special wire penetrating slot forming tool to form axial wire penetrating slots; assembling the snake bone front pitch circle with the snake bone middle pitch circles through the connecting pin roll by virtue of a special assembly tool, and assembling and connecting everytwo snake bone middle pitch circles, as well as the snake bone middle pitch circles and the snake bone rear pitch circle to form a final snake bone device by virtue of the same steps. The preparation method is reasonable in process; and the prepared snake bone does not need to rivet.