Aim To develop and validate a dynamic nomogram to predict the risk of no-reflow phenomenon (NRP) after percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI) by constructing HALP based on haemoglobin (Hb), albumin (Alb), lymphocytes (LYM), and platelets (PLT). Methods A retrospective analysis of 449 STEMI patients admitted to Nanyang Central Hospital from January 2022 to January 2024 was divided into 145 cases in the NRP group and 304 cases in the normal reflow group according to whether the patients developed NRP after surgery. HALP was calculated based on Hb, Alb, LYM and PLT observations. Independent influences on NRP risk were determined by multivariate Logistic regression analysis. Dynamic nomogram of NRP risk after PCI in STEMI patients were developed using the R language correlation software package. Results The incidence of NRP was 32.3% (145/449) among 449 patients with NRP. The HALP of patients in the NRP group was lower than that of patients in the normal reflow group (P＜0.05). The area under the curve (AUC) of HALP for diagnosis of NRP was 0.880 (0.847～0.909), and the Kappa coefficient of its optimal cutoff value ≤3.04 versus patients with accurate diagnosis of NRP was 0.612. The results of multivariate Logistic regression analysis showed that age, diabetes mellitus, and high sensitivity C-reactive protein (hs-CRP) were independent risk factors for NRP after PCI in STEMI patients (P＜0.05), and left ventricular ejection fraction (LVEF) and HALP were independent protective factors (P＜0.05). A dynamic nomogram (https://xz0311.shinyapps.io/DynNamicNRP/) based on HALP combined with age, diabetes, LVEF, and hs-CRP was effective in predicting the risk of post-PCI NRP in STEMI patients. Conclusion HALP is more effective than traditional risk factors in predicting NRP risk in STEMI patients after PCI, and the dynamic nomogram developed based on HALP will help develop personalized treatment strategies for patients with high NRP risk.