Objective To explore the relationship between serum nerve growth factor(NGF)and neurofil-amentlight-chain(NF-L)levels with the severity and prognosis of traumatic brain injury(TBI)patients,as well as their predictive value through a prospective research.Methods A total of 132 TBI patients and 132 ordinary trauma patients were collected as the observation group and the control group,respectively.TBI pa-tients in the observation group were divided into three subgroups of mild,moderate,and severe according to Glasgow Coma Scale(GCS)scores,and they were also divided into good and poor subgroups according to Glasgow Outcome Scale(GOS)scores at 6-month follow-up.Enzyme-linked immuno sorbent assay(ELISA)was used to detect serum NGF and NF-L levels in all patients after admission.Through comparison between the observation group and the control group,the relationship between TBI and serum NGF and NF-L levels was clarified.By comparing the differences between different subgroups of the observation group,the relation-ship between serum NGF and NF-L levels and the severity and prognosis of TBI was determined.Through correlation analysis,receiver operating characteristic(ROC)curve and multivariate Logistic regression analy-sis,and the predictive value of serum NGF and NF-L levels for TBI was clarified.Results Compared with the control group,serum NGF and NF-L levels were significantly increased while GCS scores were significantly decreased in the observation group(P＜0.01).In addition,serum NGF and NF-L levels gradually increased a-mong subgroups of mild,moderate,and severe groups in the observation group(P＜0.01).The area under the curve(AUC)of serum NGF and NF-L levels for predicting mild TBI were 0.924(95％CI:0.889-0.986)and 0.991(95％CI:0.982-1.000),and the cut off values were 12.5 ng/mL and 66.5 μg/mL,respectively.AUC of serum NGF and NF-L levels for predicting moderate TBI were 0.776(95％CI:0.686-0.862)and 0.837(95％CI:0.763-0.911),respectively,and AUC for predicting severe TBI was 0.950(95％CI:0.900-0.987)and 0.988(95％CI:0.971-1.000),respectively,with cut off values of 14.5 ng/mL and 157.0 μg/mL,respec-tively.Spearman correlation analysis showed that serum NGF and NF-L levels were negatively correlated with GOS scores of TBI patients(P＜0.01).AUC for predicting the prognosis of TBI patients with serum NGF and NF-L levels were 0.858(95％CI:0.776-0.932)and 0.909(95％CI:0.824-0.978),respectively,with cut off values of 13.5 ng/mL and 71.5 μg/mL,respectively.Logistic regression analysis showed that serum NGF and NF-L levels were risk factors affecting the prognosis of TBI patients.Conclusion Serum NGF and NF-L levels are significantly elevated in TBI patients and could provide reference for early assessment of inju-ry severity in clinical practice.Furthermore,elevated serum NGF and NF-L levels are associated with poor prognosis of TBI patients and are good biological indicators for predicting prognosis.