OBJECTIVE: To explore the expression and value of C-reactive protein (CRP), procalcitonin (PCT), and lactic acid (LA) in cerebrospinal fluid (CSF) in patients with intracranial infection after craniocerebral injury operation. STUDY DESIGN: A total of 133 patients with craniocerebral injury in our hospital were divided into infection group (n=63) and non-infection group (n=70) according to whether intracranial infection occurred after operation. The levels of CRP, PCT, and LA in CSF of the 2 groups were detected and their clinical values analyzed. RESULTS: The levels of CSF CRP, PCT, and LA of infected patients were higher than those of non-infected patients (p<0.001). The value of early diagnosis was analyzed by receiver operating characteristic curve, and the results showed that CSF CRP, PCT, and LA could be used for the diagnosis of intracranial infection. Patients were divided into effective group (n=45) and invalid group (n=18) according to different prognosis of infected patients, which showed that the levels of CSF CRP, PCT, and LA of patients in the invalid group were higher than those of patients in the effective group (p<0.05). The relationship among CRP, PCT, and LA in CSF of patients with intracranial infection was analyzed by Pearson's correlation coefficient, and CRP was found to be positively correlated with LA and PCT (r=0.469, 0.616, p<0.001), and LA was also positively correlated with PCT (r=0.486, p<0.001). Risk factors of intracranial infection were analyzed by multivariate logistic analysis. Operation time >4 hours, external ventricular drainage, CSF leak, intraoperative blood loss >400 mL, and high expression levels of CRP, PCT, and LA were all risk factors for intracranial infection after craniocerebral injury operation. CONCLUSION: CSF CRP, PCT, and LA can be used as early diagnostic indicators of intracranial infection and are related to the prognosis of patients, and their high levels are the risk factors of intracranial infection. © Science Printers and Publishers, Inc.