Objective To evaluate the value of cerebrospinal fluid neurofilament light chain (CSF-NfL) levels in early diagnosis and prognosis of children with Guillain-Barre syndrome (GBS). Methods The clinical data of children with GBS admitted from November 2020 to May 2022 were retrospectively analyzed, and the children diagnosed with migraine and psychological disorders during the same period were selected as the control group. The level of CSF-NfL was compared between the two groups, and the correlation between the level of CSF-NfL and clinical characteristics was analyzed. Results There were 26 children (14 boys and 12 girls) in the GBS group, with a median age of 5.0 (3.8-8.0) years. The control group consisted of 48 children (30 boys and 18 girls) with a median age of 8.0 (5.0-9.0) years. At admission, the levels of CSF-NfL and CSF protein in the GBS group were higher than those in the control group, and the difference was statistically significant (P<0.05). The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of CSF-NfL combined with CSF protein levels in the early diagnosis of GBS were 92.3%, 95.8%, 92.3%, 95.8% and 94.6%, respectively. The CSF protein level at admission and Hughes functional score at the peak of disease were significantly positively correlated with CSF-NfL level in children with GBS (P<0.05). The CSF-NfL levels of GBS patients with poor prognosis were significantly higher than those of patients with good prognosis, and the difference was statistically significant (P<0.05). Conclusions The CSF-NfL levels were associated with CSF protein levels, disease severity and short-term prognosis, which may be helpful for the early diagnosis and prognosis evaluation of GBS.