The invention belongs to the field of tool path optimization, and specifically discloses a tool path optimization method for automatically generating a safety cylinder of a tire mold. The method comprises the steps of triangulating a CAD model of a tire mold, and obtaining initial coordinates of three vertices of all triangular slices on the surface of the tire mold, thus obtaining initial coordinates of N vertices in total; establishing a standard coordinate system, and converting the obtained initial coordinates of the N vertices into the standard coordinate system; establishing a target coordinate system according to the standard coordinate system and by combining characteristics of the mold; finding two arc boundaries according to the target coordinate system, and then obtaining the center of circle of the two arcs according to points on the boundaries, so as to determine the axis and radius of a safety cylinder; building a safety cylinder based on the axis and radius of the safetycylinder; and reducing the part where a cutter is lifted too high in the tool path to the surface of the safety cylinder to optimize the tool path. The method of the invention can effectively improvethe machining efficiency and ensure the machining precision, and has the advantages of convenience in operation, strong applicability and the like.