To provide a scientific basis for the anatomical regional division of the right anterior liver lobe via classification statistics and analysis of the third-level branches of the portal vein in the right anterior liver lobe, the ventral branch of segment Ⅵ (P6a), and the anterior fissure vein (AFV) based on CT three-dimensional visualization technology. Methods    Retrospective analysis was performed on imaging data from 100 patients who underwent contrast-enhanced upper abdominal CT scans at the Hepatobiliary Surgery Department of the Air Force Characteristic Medical Center between September 2022 and December 2024. The courses and types of third-order portal vein branches in the right anterior section, the detection frequency of the AFV, the types of hepatic veins it drained into, its drainage location, and whether the ventral branch of segment Ⅵ portal vein supplies segment S5. Results    The portal veins of the right anterior section were classified into four types: cephalocaudal (34.0%), dorsoventral (32.0%), trifurcation (24.0%), and quadrifurcation (10.0%). The overall detection rate of AFV was 89.0% (89/100). AFV detection rates were 85.3% in the cephalocaudal, 93.8% in the dorsoventral, 87.5% in the trifurcation, and 90.0% in the quadrifurcation, with no significant inter-group differences in detection rate (P=0.720) or length distribution (P=0.097) of AFV. Among the patients with single AFV trunk, 60.8% (31/51) had an AFV diameter of 2-3.9 mm, and 33.3% (17/51) had an AFV diameter of ≥ 4 mm. In patients with multiple AFV trunks, all had at least one AFV with a diameter of ≥ 2 mm. Anatomical localization revealed 96.1% (124/129) of AFV drainage points were in the proximal hepatic vein segment (≤5 cm from inferior vena cava). Among single-trunk AFV, 78.4% (40/51) drained into the proximal MHV/RHV region, with 45.1% (23/51) predominantly draining into the proximal anterior segment of MHV. Conclusion    While the dorso-ventral subdivision pattern exists in the portal vein in the right anterior lobe of the liver, it is not the dominant classification. Based on the characteristics of portal venous supply, subsegment P6a should be categorized within segment S5. Furthermore, the AVF serves as a reliable landmark for defining the boundary between the ventral and dorsal portions of S8.