Objective To investigate relationships between the expression of Bcl-2, Bax protein and neuronal apoptosis in hippocampus of posttraumatic stress disorder (PTSD) rats. Methods The SPSmethod was used to set up the rat PTSD models. There were five groups：after SPS 1d，4d，7d，14d groups and control group. Apoptotic cells were detected by electron microscopy and TUNEL method. The expressions of Bcl-2 and Bax proteins were detected with immunohistochemistry, double fluorescent, confocal laser scanning microscopy and Western blotting. Results Apoptotic cells were present in hippocampus of PTSD rats. The number of apoptotic cells increased with the development of PTSD and peaked on the 7th day after SPS, then decreased gradually. The expression of Bcl-2 protein peaked on the 4th day after SPS and Bax protein peaked on the 7th day after SPS, then decreased gradually. The ratio of Bcl-2/Bax increased at the beginning and then gradually decreased. Conclusion The neuronal apoptosis in hippocampus of PTSD rats may be one of reasons inducing hippocampus atrophy. The increase of Bcl-2 and Bax protein and the change of Bcl-2/Bax ratio would play an important role in regulating the hippocampal neuronal survival