Fifty healthy male Wistar rats were randomly divided into normal control group， Pb injury model group（Pb group）， Pb+low， medium and high doses of Se-Met groups（Pb+L Se-Met group， Pb+M Se-Met group， Pb+H Se-Met group）（n=10）. In addition to normal control group， the rats in other 4 groups were fred to drink lead acetate solution with a concentration of 1 g·L^－1 （546.2 mg·L^－1 Pb） to establish the lead-damaged rat models. After 4 weeks the rats in low， medium， and high doses of Pb+Se-Met groups received 0.1，0.2^{and 0.4 g·kg－1 Se-Met and administrated with 5 mL distilled water suspension by gavage every day；the rats in normal control group and Pb group were given equal volume of distilled water every day for 6 weeks. After 6 weeks， the bone lead content of the rat was measured by graphite furnace atomic absorption spectrometry；Morris water maze experiment was carried out to detect the behavior indexes of the rats. The activities of glutathione peroxidase（GSH-Px）， superoxide dismutase （SOD） and cholinesterase（CHE） and the levels of malondialdehyde （MDA）and nitric oxide （NO）in brain tissue of the rats were detected by chemical colorimetry. HE staining was used to observe the patholmorphology of the rat hippocampus CA1 region. Immunohistochemistry was used to observe the expressions of B cell lymphoma-2（Bcl-2）， Bcl-2 associated X protein（Bax）， and selenoprotein S（Sel S） in the rat hippocampus CA1 region in various groups.}

Compared with normal control group， the bone lead contents of the rats in Pb group， Pb+L Se-Met group， Pb+M Se-Met group and Pb+H Se-Met group were significantly increased（P<0.01）， the escape latencies and the movement distance of the rats in Morris water maze experiment rats were significantly increased （P<0.01），the residence time in target quadrant and the across times were significantly reduced （P<0.05），the activities of GSH-Px， SOD and CHE in brain tissue of the rats were significantly decreased（P<0.01）， and the levels of MDA and NO were significantly increased （P<0.01）. Compared with normal control group，the nerve cells in hippocampal CA1 region of the rats in Pb group didn’t arrange neatly， the morphology of cells was irregular，presenting polygon，and the nuclei were concentrated and hyperchromatic.Compared with Pb group， the bone lead contents of the rats in Pb+L Se-Met group， Pb+M Se-Met group and Pb+H Se-Met group were significantly reduced（P<0.01），the escape latencies and the movement distance of the rats in Morris water maze experiment were significantly reduced （P<0.01）， the residence time in taget quadrant and the across times were significantly increased（P<0.05），the activities of GSH-Px， SOD and CHE were increased（P<0.01），and the levels of MDA and NO were significantly reduced（P<0.01）； the pathological changes in hippocampal CA1 region of the rats were improved， the expression amounts of SelS and Bcl-2 proteins were increased，and the Bax protein expression amounts were reduced.

Se-Met has a protective effect on the brain tissue damage of the rats exposed to lead， and its mechanism may be related to reducing the lead load in the body of the rats exposed to lead， reducing oxidative damage， apoptosis in hippocampus CA1 region of brain， and increasing the expression of SelS in CA1 region in hippocampus of the rats.