The survival dynamics of recombinant Sinorhizobium fredii HN01DL,Bradyrhizobium japonicum TA113QD both of which marked with luxAB gene and its wild-type strain HN01,TA11 in sterilized and non-sterilized soil microcosm were studied respectively1 The results showed that the population dynamics of HN01Dl and TA113QD in sterilized and non-sterilized soil microcosm was obviously different1 The survival population of the marked rhizobia decreased slightly at an early stage after inoculation and then kept a relatively stable high survival level in sterilized soil microcosm,and its survival population in non-sterilized soil microcosm decreased regularly at a high speed until reaching about 4.5 log cfu g^-1 soil1 No significant difference in soil survival was found between the recombinant marked strains and the wild-type stains.