The invention provides a screw nut tube hole structure of a ball screw. The screw nut tube hole structure of the ball screw comprises a screw, a screw nut and a circulation accessory, wherein a through hole allowing the screw to penetrate through is formed in the screw nut, the outer peripheral surface of the screw nut is provided with a plane, and the plane comprises at least one set of tube holes; and the circulation accessory is fixed to the plane of the screw nut, wherein the outline of each tube hole is formed by three or more arcs including the first arc, the second arc and the third arc, the first arc, the second arc and the third arc of each tube hole are hinged to one another through a straight line, the first arc, the second arc and the third arc of each tube hole have a first circle center, a second circle center and a third circle center correspondingly, a center connection line is formed between each first circle center and the corresponding third circle center, and each the center connection line is perpendicular to the axis of the screw.