To explore the changes in the expression level of neuron-specific enolase (NES) in the cerebrospinal fluid of patients with subarachnoid hemorrhage (SAH) and its clinical significance.

Sixty-four SAH patients who were hospitalized in Neurosurgery Department of People’s Hospital of Huadu District from January 2018 to June 2020 were selected as the study group. Sixty-four patients who had undergone lumbar anesthesia in our hospital for non-neurological diseases were selected as the control group. The cerebrospinal fluid samples were taken by lumbar puncture on the 1^st, 3^rd, 5^th, 7^th, 10^th and 14^th days after the onset of the study group, while the control group left cerebrospinal fluid samples when they were under spinal anesthesia, and the NSE expression level was detected and the expression of NSE was compared with the change of the expression. The patients in the study group were divided into groups according to etiology, NIHSS score and GOS score, and compared the NSE expression level in cerebrospinal fluid of each subgroup.

The expression level of NES in cerebrospinal fluid of the study group began to increase on the 1^st day after onset, reached the peak on the 3^rd to 5^th day, and then gradually decreased, and the normal level was basically recovered on the 14^th day. There was no significant difference in the expression of NSE in cerebrospinal fluid between different etiological subgroups in the study group (P>0.05); There was significant difference in NSE expression in CSF between different NIHSS and GOS score subgroups (P<0.05).

NSE expression level in cerebrospinal fluid of SAH patients increased after onset, and reached the peak on the 3^rd to 5^th day. The expression level of NES was related to the degree of nerve damage and prognosis, which could be used as the index of neurological function damage and prognosis assessment.