BACKGROUND: Chronic normal pressure hydrocephalus (CNPH) is a recognized sequela of aneurysmal subarachnoid haemorrhage (ASAH). Ventriculoperitoneal shunt (VPS) is a conventional treatment for hydrocephalus, though its effectiveness for CNPH post-ASAH remains unclear. METHODS: We included ASAH patients with CNPH who underwent VPS surgery. Changes in the modified Rankin Scale (mRS) before and after surgery were analysed to evaluate VPS benefits. The least absolute shrinkage and selection operator (LASSO) identified relevant variables and predictive models were constructed using eight supervised machine learning algorithms to assess VPS benefit. RESULTS: Among 75 patients (39 males and 36 females), 48 (64%) benefited from VPS, while 27 (36%) did not. The beneficial group showed a longer disease course, higher cerebrospinal fluid (CSF) pressure, lower red and white blood cell counts in CSF and lower modified Fisher (MF) and Hunt-Hess (HH) grades compared to the non-beneficial group. Univariate logistic regression analysis indicated that disease course, CSF pressure, RBC/WBC counts in CSF, WBC count in blood, MF grade, HH grade and preoperative mRS were associated with favourable VPS outcomes. The Xtreme Gradient Boosting (XGB) model demonstrated the highest area under the curve (AUC) of 0.946 and lowest residual error. A nomogram was subsequently developed and demonstrated a satisfactory performance. CONCLUSION: VPS benefits in CNPH patients after ASAH were associated with disease course, CSF pressure, RBC/WBC counts in CSF, WBC count in blood, MF and HH grades and preoperative mRS. The XGB model demonstrated optimal predictive performance, with an AUC of 0.946.