Anatomical differences of unilateral percutaneous kyphoplasty (PKP) between transverse process-pedicle approach (TPPA) and conventional transpedicular approach (CTPA) are not well discussed. To investigate the anatomical distinctions of unilateral PKP between TPPA and CTPA, we have discussed the unilateral PKP through a 3-dimensional-computed tomography database. Five hundred lumbar spines from 100 patients have been retrospectively collected and unilateral CTPA and TPPA were simulated. Distance between the entry point and the midline of the vertebral body (DEM), the puncture inclination angle (PIA), and the success rate (SR) of puncture were measured and compared. The male presented with significantly larger DEM than the female. The TPPA group presented with larger DEM than the CTPA group according to different level, the difference was 1.5 +/- 1.1 mm to 3.8 +/- 2.3 mm. The PIAs in the TPPA group were larger than that in the CTPA group. The SR including 1 side SR and bilateral SR was 72.0% in the CTPA group and 98.0% in the TPPA group. Compared with CTPA group, the SR in TPPA group was significantly higher for L1 to L4 no matter in the left, right side and female patients. The TPPA group presented with more lateral entry point, larger PIAs and higher SRs than that in the CTPA group. PKP surgery through a TPPA was safer and could provide a more symmetrical distribution of bone cement than the CTPA group.