[Objective] To propose a new reference method and related anatomical parameters for anterograde screw placement in the posterior column of the acetabulum to provide a basis for the design of the late guide plate. [Method] Collect 40 adult pelvis CT data, and reconstruct the three-dimensional model with mimics software. Insert a cylinder and adjust it to the ideal position. The exit point (A) of the cylinder from the inner side of the iliac wing is used as the entry point of the lag screw, and the exit point (B) under the ischial tuberosity is used as the exit point of the lag screw. Nail point, take point C on the arcuate edge, make AC the shortest distance from point A to the arcuate edge, point D is the most anterior edge of the sacroiliac joint, connect AC, CD;A flat region of the quadrilateral plate near the posterior edge of the greater sciatic notch was found on mimics, make a plane β parallel to this area,and make a plane γ perpendicular to the plane β and tangent to the posterior edge of the ischial notch. Measure the distance between AC and CD, the maximum radius and length of the lag screw, the angle between the lag screw and the plane β (a) and the angle between the lag screw and the plane γ (b). [Results] In the comparison between males and females of the same side, the maximum radius, maximum length, and line CD of the screw were statistically significant (P<0.05), and the line AC, included angle a and included angle b were not statistically significant ( P>0.05); In the comparison between the left and right sides of the same sex, the maximum radius, maximum length, line AC, CD, included angle a and b of the screw were not statistically significant (P>0.05). [Conclusion] According to the relevant anatomical data, the nail placement process is more accurate and safer, and it provides a basis for the later design of the guide plate.