Abstract: The purpose of this study was to assess the effect of passive cigarette smoking on histopathological structure of lung tissues in mice. After treated with cigarette smoke fumigation, the lung tissues samples of the experimental mice were collected to prepare paraffin slices. HE staining method was used to dye the tissue slices, and the changes of pulmonary histopathological structure were microscopically observed. The results showed that after treatment of fumigation, the observed pulmonary histopathological changes of the mice were compromised of alveolar enlargement, alveolar wall thinning, tissue hyperplasia in alveolar septum at different degrees, alveolar sac and alveolar tube enlargement or damage, bronchiole wall injury, increased number and messy arrangement of epithelial columnar cilia cells in mucosa, foreign matter accumulation in the narrowed tube cavity, and severely damage in mucosa rugae of thickened terminal bronchioles. In addition, compared to the juvenile mice, the changes of pulmonary histopathological structure caused by cigarette smoking fumigation were more obviously observed in adult mice. The combined data suggest that with the extension of fumigation treatment duration, some substances in cigarette smoke can result in obvious histopathological changes in lung tissues in mice, and the impact of cigarette smoke on pulmonary histopathological structure is more serious in adult mice than in juvenile mice.