Traumatic brain injury(TBI) is a leading cause of death and disability in individuals worldwide.Producing a clinically relevant TBI model in small-sized animals remains fairly challenging.For good screening of potential therapeutics,which are effective in the treatment of TBI,animal models of TBI should be established and standardized.In this study,we established mouse models of closed head injury using the Shohami weight-drop method with some modifications concerning cognitive deficiency assessment and provided a detailed description of the severe TBI animal model.We found that 250 g falling weight from 2 cm height produced severe closed head injury in C57BL/6 male mice.Cognitive disorders in mice with severe closed head injury could be detected using passive avoidance test on day 7 after injury.Findings from this study indicate that weight-drop injury animal models are suitable for further screening of brain neuroprotectants and potentially are similar to those seen in human TBI. Traumatic brain injury (TBI) is a leading cause of death and disability in individuals worldwide. Producing a clinically relevant TBI model in small-sized animals is fairly challenging. For good screening of potential therapeutics, which are effective in the treatment of TBI, animal models of TBI should be established and standardized. in this study, we established mouse models of closed head injury using the Shohami weight-drop method with some modifications concerning cognitive deficiency assessment and provided a detailed description of the severe TBI animal model. We found that 250 g falling weight from 2 cm height produced severe closed head injury in C57BL / 6 male mice. Cognitive disorders in mice with severe closed head injury could be detected using passive avoidance test on day 7 after injury. Findings from this study indicate that weight- drop injury animal models are suitable for further screening of brain neuroprotectants and potentially similar to those seen in human TBI.