Objective 　To study the effects of enzymatic activity of superoxide dismutase (SOD) and catalase (CAT)，and maleic dialdehyde (MDA) content and histological structure in the lungs of the developing filial mice and mother mice. Methods Totally 48 female mice at the eighth day of pregnancy were injected with different concentrations (1.0g/L，1.5g/L and 2.0g/L) of heroin (0.2ml) and the same amount of saline in the morning and afternoon until the birth of filial mice. Changes in the enzymatic activity of SOD，CAT and MDA content were respectively analyzed by colorimetry and the lung structure of filial mice and mother mice were observed by microscopy at embryo 15 days and postnatal ages of 1day, 7days and 15days. Results There was a significant inhibition for the CAT and SOD activity (EM>P/EM><0.05) following heroin adminstration，and the inhibitive effects were stronger with increasing concentration of heroin increasing; however, the MDA content significantly increased (P<0.05) and was higher with increasing concentrations of heroin. The diameter of the alveolous and thickness of interalveolar septum of filial mice and mother mice were significantly increased (EM>P/EM><0.05) with injection of 1.5g/L or 2.0g/L heroin than that of the controls at the different developmental stages.Conclusion The lungs of filial mice and mother mice at the different developmental stages were damaged in different degrees by heroin. This damage might be correlated with the low activities of SOD, CAT and high cont