Karyotypes and evolutionary trend of 32 Polygonum multiflorum germplasm resources were studied via squash method.The results showed that:(1)The ploidy levels were divided into diploid (2n=2x=22) and triploid (2n=3x=33).Asymmetry index As.K% and AI value ranged from 51.85% to 61.52% and from 0.37 to 1.40,respectively.The karyotypes of all the test materials consisted of “m” and “sm” chromosomes,which include “1A”,“1B” and “2A”.The results indicated that the evolutionary degree of P.multiflorum was relatively low.(2)53.13% germplasms were triploid in 32 germplasm resources,which showed that polyploidization played an important role in the evolution of P.multiflorum.However,chromosome structural variation was one of the most important evolutionary ways.(3)Chromosomal morphological change of 32 germplasms resources was divergent and evolutionary degree was not consistent.The results showed that the existence of different ploidy levels is associated with the different habitats.(4)The primal centre of origin of P.multiflorum may be in the high latitudes,the chromosomal morphology and structures varied gradually when P.multiflorum migrated to low latitudes.