The invention discloses an axial circulation type ball screw. The axial circulation type ball screw comprises a screw body, and the screw body is provided with main bearing faces, wherein the two ends of a backflow assembly are arranged on the main bearing faces. The distance between each main bearing face and the axis of the screw body is defined as the first height H, the distance between the highest point of rolling pieces flowing in a backflow channel and the axis of the screw body is defined as the second height Hmax, and each main bearing face is set to meet the formula of Hmax-0.5*BD<=H<=Hmax, wherein BD is the bead diameter of each rolling piece; and in this way, the situation that because the height of each main bearing face is larger than the second height Hmax, the thickness of the backflow assembly is not large enough and the situation that because the height of each main bearing face is smaller than Hmax-0.5*BD, the amount of cutouts of the screw is large, and the rigidity of the screw is lowered are avoided.