目的：研究苯多次吸入对小鼠的致微核作用。方法：采用静式吸入染毒的方法，苯浓度为１／８～１／６４ＬＣ５０，随机分为４组，每隔２４ｈ染毒１次，每次２ｈ，共３０ｄ；另设对照组。染毒结束后，取血作白细胞计数，取胸骨骨髓作微核计数。白细胞计数的比较用Ｆ检验，微核率的比较用率的ｕ检验。结果：白细胞计数在正常值范围，实验组与对照组差异无显著性（Ｐ＞０．０５）；但微核率，实验组比对照组明显增高（Ｐ＜０．０１），且有剂量反应关系。结论：苯长期吸入染毒可引起骨髓细胞遗传物质的损伤，且早于外周血白细胞总数的变化。 Objective: To study the micronuclei induced by multiple benzene inhalation in mice. Methods: By inhalation of inhalation, the concentration of benzene was 1/8 ~ 1 / 64LC50, which were randomly divided into 4 groups. After the end of the exposure, blood was collected for white blood cell counting, and the bone marrow was taken for micronuclei counting. Comparison of white blood cell count using the F test, micronucleus rate of comparison u test. Results: There was no significant difference between the experimental group and the control group (P> 0.05). However, the micronucleus rate in the experimental group was significantly higher than that in the control group (P <0.01) Reaction relationship. Conclusion: Long-term inhalation of benzene can cause the damage of genetic material of bone marrow cells, and earlier than the change of the total number of peripheral leukocytes.