The invention discloses a screw rod milling cutter design method based on the form and position geometry. The method comprises the following steps that a spiral line equation corresponding to different discrete points on the screw rod end surface is obtained according to geometrical parameters of a screw rod to be processed; each spiral line is solved to obtain a distance from each spiral line to a milling cutter axial line, and in addition, the position coordinates of a point with the shortest distance from each spiral line to the milling cutter axial line; a tooth-shaped curve of a milling cutter is obtained according to the position coordinates of the point with the shortest distance from each spiral line to the milling cutter axial line. When the method is used for designing the screw rod milling cutter, the solving processing is simple, and in addition, the precision is higher.