In order to improve the sealing performance of the CO₂ slant disc axial plunger pump distribution pair，a spiral groove dynamic pressure hole was opened on the surface of the rotating cylinder of the plunger pump.The sliding mesh transient numerical simulation technology was used to compare and analyze the sealing performance of the planar distribution pair liquid film and the spiral groove distribution pair liquid film.The results show that compared with the unopened planar liquid film，the leakage volume of the spiral groove‑type distribution pair liquid film is significantly reduced，with the leakage volume reduction of 34.17%.The flow velocity of the liquid film area near the waist groove in the high‑pressure zone is higher，which is the main area of leakage.While in the liquid film area near the waist groove in the low‑pressure zone，the fluid only flows in the liquid film，and almost no fluid flows out，and the leakage can be negligible.The volume of leakage to the plunger pump housing side is the largest，accounting for approximately 61.5%，followed by the amount of leakage to the pump shaft，accounting for approximately 35.99%.The volume of leakage to the waist groove side of the low‑pressure area is the smallest，accounting for approximately 2.51%.Driven by the rotation of the spiral groove，the periodic extrusion fluid produces a dynamic pressure effect，the opening force of the liquid film becomes larger，and the dynamic pressure effect of the spiral groove‑type dispensing pair liquid film is stronger.The research results can provide a reference for the optimization of the sealing performance of the distribution pair.