To demonstrate genetic divergence of different populations of exotic Radopholus simils in China,analyze their phylogenetic relationship,and provide scientific proof for the origin of these populations,the published universal primers were used to amplify the rDNA-ITS sequences of progeny of single and 25 females,respectively,from 20 populations of R. similis. The amplified products were sequenced,blasted and aligned with public submitted sequences and phylogenetic tree was then constructed. The rDNA-ITS sequenced was 705-713 bp in length,and showed high similarity (≥95%) among different populations,with a divergence of 0-7.5%. The rDNA- ITS1 and ITS2 were 273-276 bp and 151-152 bp in length,with sequences similarity ≥98.58% and ≥98.35%,respectively. The sequences alignment results showed that the ITS sequences had a very high similarity between the progeny of single female and multiple females in the same population,showing 100% sequence identity in 8 populations and ≥97% similarity in the other populations. In addition,the phylogenetic tree with Pratylenchus coffeae as outgroup showed that all R. similis populations were clustered together,but with 4 small branches. Among them, Anthurium andraeanum population RsW was clustered in a single branch,Philodendron sp. population RsH had a longer genetic distance with other members in the same branch,but Calathea zebrine population RsP and C. makoyana RsS had a shorter genetic distance. The results indicated that the R. similis populations in China mainly came from the European Marantaceae and Araceae ornamentals,and the primary origin for the former was banana in Sudan and was complicated for the latter．