【Abstract】Objective To measure the anatomical parameters of lumbar percutaneous pedicle cortical screw in middle-aged and elderly people and analyze the feasibility of percutaneous screw placement.Methods Three-dimensional CT data of 50 middle-aged and elderly people were selected and imported into Aquarius iNtuition Viewer V4.4.6 software. The screw insertion angle, safety range, screw diameter and length, the distance between skin screw insertion point and vertebral upper endplate and the distance between screw insertion point and spinous process axis were measured.Results There was no significant difference in the distance from the skin nail entry point to the vertebral upper endplate (P>0.05), but there was significant difference in the distance from the nail entry point to the spinous process axis (P<0.05). The screw diameters of L1-L5 segments gradually increased in cross section, and the difference was statistically significant (P < 0.05). The actual length of screws in different segments has statistical significance (P<0.05), and the actual length of screws in male segments is greater than that in female segments, with statistical significance (P < 0.05). The ideal external deviation angle of screws in each segment of lumbar spine was consistent, and there was no significant difference (P>0.05). The screw diameters of L1-L5 segments in sagittal plane gradually decreased, and the difference was statistically significant (P<0.05), while there was no significant difference in the screw diameters of lumbar vertebrae between sexes (P>0.05). There was no significant difference in the ideal head inclination angle between L1 and L5 (P>0.05), and there was no significant difference in the ideal head inclination angle between the sexes (P>0.05).Conclusion Through the distance from the upper endplate of vertebral body to the midline of spinous process, we can find out the body surface positioning point of percutaneous pedicle cortical screw, which is different among different segments. This point can provide reference for the placement of percutaneous pedicle cortical screw in middle-aged and elderly people.