〔Abstract〕 Objective To study the neuropathological changes and process brain astrocyte microglia and neuron injury in rats at different time after mild blast-related traumatic brain injury(bTBI), and to investigate the neuroprotective potential of dietary supplementation with fish oil on mild bTBI rats. Methods 54 newly weaned SD rats were randomly divided into control group(n=18), model group(n=18) and treatment group(n=18). The model group and treatment group were fed with ordinary diet and oil-rich diet for 33 days to establish the mild bTBI model by shock wave, respectively. The control group rats were fed with ordinary diet without shock wave injury. Results Compared with control group, the weight of rats in the model group and treatment group decreased to a certain extent within 2 days after injury, and then recovered to the level before injury. After bTBI injury for 6 h, 24 h and 3 d, the number of GFAP positive staining astrocytes and vertebral cells in hippocampal area decreased in both model group and treatment group, whereas the number of activated microglia and apoptotic neurons in the hippocampus increased in a time-dependent manner in model group and treatment group. In addition, compared with the model group, the treatment group with oil-rich diet increased the number of astrocytes and pyramidal cells in the hippocampus after injury, and decreased the number of activated microglia and apoptotic neurons in the lesions area. Conclusion Pre-injury dietary supplementation with fish oil shows neuroprotective benefits in alleviating neurons injury and inhibiting neuroinflammatory response in a rat model of mild bTBI.