Abstract: Objective To investigate clinical relevance between the level of the serum cystatin C (CysC) and Guillain-Barré syndrome (GBS), and the discrepancy in the levels of CysC between serum and cerebrospinal fluid (CSF) in patients with GBS. Methods Total 30 cases of GBS in our department from December 2015 to February 2018 were collected as GBS group, while other 30 patients undergoing spinal anesthesia were collected from Orthopedics department and General surgical department as the control group. The levels of CysC in serum and cerebrospinal fluid and other clinical data were collected in the two groups. Results ①There was no statistically difference in the levels of CysC in the cerebrospinal fluid between the two groups, P=0.450. ②The level of serum CysC in the GBS group was higher when compared with the control group (P=0.005); The level of serum CysC in patients with severe GBS increased significantly as compared with the patients with mild GBS, the difference was statistically significant (P=0.012). ③There was a positive correlation between serum CysC level and Hughes score in GBS patients (r=0.759, P<0.001), however, there was no correlation between CSF CysC level and Hughes score in GBS patients (P>0.05). ④The Hughes score of GBS patients was positively correlated with age, serum CysC and cerebrospinal fluid protein, and negatively with the precursor events, but not with the level of CSF CysC and sex. ⑤Taking Hughes score as the dependent variable, taking precursor events, serum CysC, cerebrospinal fluid protein and age as independent variables, we found that the levels of serum CysC and cerebrospinal fluid protein were risk factors of Hughes score. Conclusion Serum CysC may be used as an indicator of the severity of GBS patients; the levels of serum CysC and cerebrospinal fluid protein are the risk factors of limb paralysis in GBS patients.