脊葫灰质炎减毒活疫苗中皿２减毒株是我国已用于人群免疫的疫苗株之一，具有较好的免疫原性及稳定的神经毒力安全性。为探讨中ｍ２株同ｓａｂｉｎ皿型株的相互关系，应用ＲＴ—ＰｃＲ法，克隆了中Ⅲ２株７９４个核苦酸序列。通过核苦酸序列分析、体外特征实验、猴体神经毒力实验发现，中Ⅲ２：株同Ｓａｂｉｎ皿型在核苦酸序列上存在差异。同时，中Ⅲ２株的猴体神经毒力明显低于ＳａｂｉｎⅢ型。结果提示，中ｍ２株同ｓａｂｉｎ皿型之间在基因结构及生物学性状上存在差异。 Live attenuated poliovirus vaccine in dish 2 attenuated strain is one of vaccine strains that has been used in population immunization in our country, and has good immunogenicity and stable neurotoxicity safety. In order to explore the relationship between M2 and sabin-type strains, RT-PcR method was used to clone 794 nucleotide sequences in Zhong2 and 2 strains. Nucleotide sequence analysis, in vitro characteristics experiments, the monkey virulence test found that in the Ⅲ 2: Sabin type with nucleotide sequence differences. At the same time, the neurovirulence of the monkey in stage Ⅲ 2 was significantly lower than that of Sabin Ⅲ. The results suggest that there are differences in gene structure and biological characters among the M2 strains and the sabin type strains.