Objective To explore the effect of secondary brain injury(SBI) in high-risk factors and brain malignant encephaiocele during surgical operation for severe traumatic brain injury. Methods Carried on the grouping graduation to 112 patients with severe traumatic brain injury according to SBI's high-risk factors:non-high-risk factors group (pure group) 23 cases, high-risk factors group (SBI group) 89 cases, 1 level of high-risk factors group had 27 cases, 2 level of high-risk factors group had 28 cases, 3 level of high-risk factors group had 34 cases. Results Carried on the comprehensive therapy regarding the above patients, the brain malignant encephalocele rate in the SBI group and the pure group was 59.55% (53/89) and 13.04%(3/23) respectively, there was significant statistics differences in the two groups,1 level and 2 level of high-risk factors group of brain malignant encephalocele rate was 40.74% (11/27) and 53.57% (15/28) respectively, the difference was not obvious statistics significance, 2 level and 3 level of high-risk factors group of brain malignant eneephalocele rate was 53.57%(15/28) and 79.41%(27/34) respectively, the difference was obvious statistics significance. Conclusions The SBI's high-risk factors are the important factors affecting severe craniocerebral injury encephalocele. Taking adequate pre-operative assessment, carrying a comprehensive treatment on the patients combine with high-risk factors of SBI can greatly reduced the incidence of brain malignant encephalocele during surgical operation if the high-risk factors of SBI is controlled.