Abstract: 32 femalerats were divided into four groups.One group took as control,the other three groups received.manganese chloride (MnCl₂)as intraperitioneal injection every two days for two weeks,the dose were 7.5,15 and 30 mg/kg respectively.After pregnant the mother-rats received MnCl₂ unceasingly for a week with the same method as before.The levels of HSP70 in the livers of the new-born rats were deter mined with western-dot-blotting, and the activity of SOD were determined simultaneously.The activity of SOD in the livers of new-born rats of 15mg/kg group were lower than the control group(P<0.05);the levels of HSP70 in the livers of new-born rats of three groups that mother-rats exposed to the manganeses increased significantly(P<0.01) compared with the control.Exposure to MnCl₂ of mother-rats could induce HSP70 synthesis in the livers of new-born rats,but the mechanism of this effect in the embryonic developtoxicity of Mn remain to be delineated.