Abstract: OBJECTIVE To explore the changes of sensitivity of blood biochemistry and cerebrospinal fluid（CSF）-related indexes in patients with central nervous system（CNS） infection so as to provide guidance for early diagnosis of CNS infection. METHODS During the period from Dec. 2017 to Aug. 2019, 264 adult patients with CNS infection who were admitted to Yuyao People's Hospital were enrolled as the observation objects. A total of 102 adult patients without CNS infection who were admitted during the same period were enrolled as the control group. Clinical data, variations in blood biochemistry and CSF related indexes were compared between the two groups. ROC curves were applied to analyze predictive value of blood biochemistry and CSF related indexes for CNS infection. RESULTS Among 264 adult patients with CNS infection, there were 125 cases with purulent infection, 72 cases with tuberculosis infection and 67 cases with viral infection. The comparison results of baseline data between the two groups showed that white blood cell count（WBC） and level of lactic acid in the observation group were significantly higher than that in the control group（P＜0.05）. C-reactive protein（CRP） and lactate dehydrogenase（LDH） levels in serum and CSF in the observation group were significantly higher than that in control group（P＜0.05）, whereas contents of cholinesterase（CHE） in serum and CSF were significantly lower than that in the control group（P＜0.05）. The results of receiver operating characteristic curves（ROC curves） showed that the areas under the ROC curves（AUC） of CRP, LDH and CHE in serum to that in CSF were 0.815/0.915, 0.790/0.860, 0.754/0.787, and the sensitivity of them were 0.572/0.788, 0.621/0.803, 0.803/0.674. AUC of CRP and CHE in CSF were significantly higher than that in serum（P＜0.05）. CONCLUSION The levels of CRP, CHE and LDH in serum and CSF are of certain predictive value for adult CNS infection. The predictive value of CRP and CHE in CSF is better than that in serum for infection.