Objective To investigate the predictive value of the pre-treatment hemoglobin-albumin-lymphocyte-platelet HALP score for overall survival in patients with esophageal squamous cell carcinoma ESCC undergoing radical radiotherapy and to construct a nomogram model to evaluate its predictive performance. Method A retrospective analysis was conducted on 246 patients with stage Ⅲ/ Ⅳ ESCC admitted to Sichuan Cancer Hospital from March 2012 to November 2018. The pre-treatment HALP score was calculated and the optimal cutoff value was determined using X - tile. The correlation between HALP and clinicopathological features was analyzed. Prognostic factors were assessed using the Kaplan-Meier method and Cox regression models. A nomogram was constructed and its predictive performance was validated. Result The low HALP group was significantly associated with more advanced T stage N stage and clinical stage P < 0. 05 . The high HALP group showed significantly better 1- 3- and 5-year overall survival rates compared to the low HALP group 74. 7% vs 54. 0% 46. 6% vs 25. 6% 36. 9% vs 19. 8% P < 0. 001 . Multivariate Cox proportional hazards regression model analysis identified drinking history T stage and HALP as independent prognostic factors for overall survival P < 0. 05 . The nomogram model for predicting overall survival had a C - index of 0. 687 demonstrating good predictive performance and calibration plots indicated high predictive accuracy. Conclusion A low pre-treatment HALP score is an independent poor prognostic factor for overall survival in ESCC patients undergoing radical radiotherapy. The HALP-based nomogram model may provide a reference for individualized prognostic assessment.