目的　检测硫芥对小鼠淋巴瘤L5 178Y3 .7.2c tk+ - 细胞的诱变性。方法　采用 96孔微孔板接种法检测平板接种效率和突变频率。结果　硫芥可诱导L5 178Y3 .7.2c tk+ - 细胞tk位点的突变 ,诱发突变是自发突变的 2～ 15倍。在tk位点诱发了大克隆和小克隆两种不同表型的突变集落 ,以小克隆为主。结论　硫芥有明确的致突变性和较强的细胞毒性 ,产生了大范围的DNA损伤 Objective To detect the mutagenicity of sulfur mustard on mouse lymphoma L5 178Y3 .7.2c tk + - cells. Methods 96-well microplate inoculation method was used to test the plating efficiency and mutation frequency. As a result, sulfur mustard induced a mutation at tk site of L5 178Y3 .7.2c tk + -cells. The induced mutation was 2 to 15 times of spontaneous mutation. At tk locus, two clones with different phenotypes, large clone and small clone, were induced, which were dominated by small clones. Conclusion Sulfur mustard has a clear mutagenicity and strong cytotoxicity, resulting in a wide range of DNA damage