The positioning device for bone drilling comprises a base, and the base has an outer wall, a positioning block, a guiding recess and an inner wall. The positioning block is formed on the outer wall of the base. The guiding recess is formed longitudinally through the base. The inner wall surrounds the guiding recess and the inner wall is a concave camber. The doctor can use the positioning block to fix the positioning device on a guide mold. A relative position between the positioning device and the guide mold can be relatively fixed. Prior to or during the drilling, the doctor can replace the positioning device with another positioning device with a more suitable diameter, oblique angle and oblique direction so that the positioning device for bone drilling can drill a hole at an accurate position, at an accurate oblique angle and in an accurate oblique direction as desired.
