Objective To investigate the serum levels of brain derived neurotrophic factor (BDNF) and heat shock protein 70 (HSP70),and evaluate their clinical significance in brain injury of children with complicated febrile convulsions (CFC).Methods Forty-three patients with CFC,41 children with simple febrile convulsions and 36 healthy controls were recruited in this study; their serum levels of BDNF and HSP70 were detected by enzyme linked immunosorbent assay (ELISA); correlation between levels of BDNF and HSP70 and both time of twitch duration and twitch frequency were analyzed.Results The mean serum concentrations of BDNF (4.96±1.21 ng/mL) and HSP70 (2.86± 0.93 ng/mL) in patients of CFC group were significantly higher than those in patients of simple febrile convulsions and healthy controls (P＜0.05); while no significant difference was noted between patients of simple febrile convulsions and healthy controls (P＞0.05).These changes were closely related to the duration time and frequency of convulsions(r=0.553,P=0.015; r=0.587,P=0.012; r=0.526,P=0.024; r=0.562,P=0.018).Conclusions It is sure that some brain injury exists in children with CFC; BDNF and HSP-70 might be one of the molecular mechanisms for the brain injury and protective effect.