Abstract： Objective:To investigate the effects of traumatic brain injury（TBI）combined with seawater immersion（SI）on hematological indexes，and heart，liver，and kidney functions，and lung and brain histopathological changes in rats.Methods:Twenty healthy male SD rats were randomly divided into sham group，TBI group，SI group，and TBI+SI group，according to the random number table method，with five rats in each group. The rats in the sham group and the TBI group were placed at room temperature 26℃ for 10 h. The rats in the SI group were immersed with their bodies in seawater at（28 ± 0.5）℃ for 10 h，and the rats in the TBI+SI group were treated with SI immediately after TBI. After modeling，the complete blood count，biochemical and coagulation indexes，myocardial enzyme profile［creatine kinase（CK）］，liver function［alanine aminotransferase（ALT）and aspartate aminotransferase（AST）］，and kidney function［blood urea（BUN）and serum creatinine（SCr）］of the rats in each group were detected. The differences of various indexes among the four groups were compared，and the pathological changes of brain and lung tissues were observed.Results:Comparing with the sham group and the TBI group，in the SI group and TBI+SI group，the erythrocyte count（RBC），hemoglobin，and hematocrit of the SD rats significantly increased after SI（ P<0.05），while white blood cell count and platelet count decreased（ P<0.05）；prothrombin time and activated partial thromboplastin time decreased（ P<0.05）；AST，ALT，BUN，and SCr all increased（ P<0.01）. After the rats with TBI being immersed in seawater，their lung tissues had bleeding，and the damage of brain tissue aggravated. Conclusion:After 10 h seawater immersion，dehydration，hyperkalemia，hypernatremia，tissue metabolism disorders，aggravated brain injury，and pulmonary tissue bleeding occurred in rats.