Objective To study the value of thromhus precursor protein(TpP)in early diagnosis of acute ischemic cerebrovascular disease.Methods The patients who showed completely or partly anterior circulation infarcts syndrome and were within 6 hours from onset on admission were observed dynamically.All patients were divided into thrombotic cerebral infarction(TCI)group(40 cases),transient ischemic attack (TIA)group(42 cases), and lacunar infarction(LI)group(37 cases).Concentrations of TpP in plasma obtained from three groups on admission were detected by enzyme linked immunosorbent assay(ELISA),then were compared with each other.The diagnostic value of plasma TpP to TCI within 6 hours from onset was analyzed with ROC curve.Results The level of TpP in TCI,TIA and LI group was(24.43±3.21),(15.51±2.65)and(13.52±5.45)mg/L respectively,and was significantly higher than that of healthy people (3.9±2.5)mg/L(P<0.01).The level of TpP was significantly higher in TCI group than that in TIA and LI group(P<0.01).The level of TpP was significantly higher in TIA group than that in LI group(P<0.01).The area under ROC curve for TpP to diagnose TCI was 0.979±0.013(P<0.01).The level of TpP on optimal cutoff was 19.1 mg/L.When the level of TpP was over 19.1 mg/L,TCI was determined with 95% sensitivity and 96%specificity, sum of which was largest of all.Conclusion The level of TpP can differentiate TCI from TIA and LI within 6 hours from onset.