This study analyzes the role of the hemoglobin, albumin, lymphocyte, and platelet score (HALP), a pre-catheterization blood parameter, in predicting the occurrence of thrombophlebitis. We recruited 268 in-hospital patients who visited the Department of Oncology of our hospital and underwent peripherally inserted central catheter between January 2021 and January 2024. The cutoff value of the HALP score was defined using receiver’s operating characteristic curve, and the differences were analyzed with log-rank test. The significance of HALP in predicting thrombophlebitis was evaluated using a multivariate Cox proportional hazards model. A total of 240 patients were enrolled and divided into a high-HALP (≥31.4) group (n = 125) and a low-HALP (<31.4) group (n = 115). The relationship between the composition of HALP and clinical pathological parameters was analyzed. HALP was significantly correlated with gender (X
2 = 4.74), limb restriction (X
2 = 3.69), performance status score (X
2 = 11.9), D-dimer (X
2 = 7.88), and platelet count (X
2 = 5.22). Multivariate regression analysis found male (hazard ratio [HR] 0.29 (0.12–0.69)), more puncture times (HR 0.01 (0.001–0.15)), lower HALP (HR 1.93 (0.82–4.52)), and sterile couplant (HR 20.6 (4.7–91.2)) were independent factors affecting the occurrence of thrombophlebitis. Receiver’s operating characteristic curve analysis showed the area under the curve of the HALP score was 0.718 (95% confidence interval 0.638–0.798), which was significantly larger than the other 3 parameters. Hence, we believe the predictive efficiency of HALP is higher than other parameters. The pre-catheterization HALP score can be used as a simple, accessible, and reliable tool for predicting thrombophlebitis in patients to undergo peripherally inserted central catheter.