Objective To explore the clinical significance of plasma CTnI, HCY and PCT levels in early diagnosis, severity and prediction in patients with acute brain injury. Methods The plasma CTnI, HCY and PCT levels in 115 patients with acute brain injury and 60 controls were determined by chemiluminescent immunoassay. The receiver-operating characteristic curve (ROC curve) was plotted to analyze the accuracy of acute plasma CTnI, HCY and PCT as a predictive indictor in the initial stage of acute brain injury. Results The plasma CTnI, HCY and PCT levels in 66 patients with heave acute brain injury were significantly higher than those in 49 cases patients with mild acute brain injury (P<0.01), and the plasma CTnI, HCY and PCT levels were increased with severity of acute brain injury. The accuracy of plasma CTnI, HCY and PCT levels as a predictive inductor by ROC curve in patients with acute brain injury were 0.038 ng/ml, 22.16 μmol/L and 0.82 ng/ml. The sensitivity was 82.4%, 76.3% and 75.8% respectively and the specificity were 75.1%, 71.2% and 69.4%, respectively. Conclusion The plasma of CInI, HCY and PCT levels might be a valuable index for the early diagnosis after acute brain injury, the evaluation of severity and prognosis in the initial stage of acute brain injury.