The present study conducted numerical simulation and technique optimization for the cooling and shaping technique of PVC-U axial hollow-wall pipe with an outer diameter of 500 mm. Utilizing established heat transfer and thermal coupling models, an investigation on the influence of cooling methods, cooling duration, cooling temperature, and vacuum negative pressure on the pipeline cooling and shaping technique was carried out. Additionally, the study involved the optimization of the cooling and shaping equipment design. The results indicate that, under the conditions of a cooling water temperature of 25 °C, a cooling duration of 1500 s, and a vacuum negative pressure of -0.09 MPa, the vacuum spray shaping technique for outer diameter shaping is the most ideal for pipeline processing. After post-optimization, the produced pipeline exhibits dimensions within the required specifications, curvature ≤0.2%, non-circularity ≤0.14%, a ring stiffness of 9.47 kN/m2, and excellent ring flexibility.