目的　研究自不同生态型和不同鼠疫自然疫源地分离的鼠疫菌 4种毒力因子的性状特征。方法　常规方法检查鼠疫菌毒力因子性状并比较在不同疫源地之间、不同生态型之间的差异。结果　 132 6株鼠疫菌中仅 1株缺失FⅠ、6株缺失PstⅠ ,Pgm和VW阳性分别为 92 99%、76 47%。结论　自我国不同疫源地、不同生态型和不同年代分离的野生型鼠疫菌绝大多数能产生FⅠ和PstⅠ ,且不同生态型和不同疫源地分离的菌株这两种毒力因子无明显差别 ,性状稳定。VW-和Pgm-菌株与生态型及疫源地有一定的关系。经长期人工培养传代后 ,4种毒力因子相比 ,VW因子较易丧失 ,该毒力因子具有更不稳定特点 Objective To study the traits of four virulence factors of Yersinia pestis isolated from natural foci of different ecotypes and different plague. Methods The conventional methods were used to examine the virulence factors of plague virulence and to compare the differences among different foci of different ecotypes. Results Only one strain out of 132 strains of Yersinia pestis lacked FⅠ. The positive rate of PstⅠ, Pgm and VW in 6 strains were 92 99% and 76 47%, respectively. Conclusion Most of the wild-type Y. pestis isolated from different foci of China, different ecotypes and different generations can produce FⅠ and PstⅠ, and there was no significant difference between the two virulence factors of isolates of different ecotypes and different foci Stable characters VW- and Pgm- strains and ecotypes and foci have a certain relationship. After long-term artificial cultivation, the VW factor is more likely to be lost than the four virulence factors and the virulence factor is more unstable