Abstract: Random amplified polymorphic DNA (RAPD) was amplified to studied genetic diversity and genetic structure of 6 populations of Erigeron breviscapus in Yunnan province.As a contrast,one population of Aster himalaicus was selected to study their phylogenetic relationship.A total of 16 primers were screened to use,and 233 bands were amplified,among which 192 (8240%) were polymorphic.At specific level,the percentage of polymorphic bands PPB,number of alleles A,effective number of alleles Ae,Nei's gene diversity H,and Shannon's Information index I were 8240%,18240,13005,01896,and 03021 respectively,and at population level were on average 5423%,15401,12691,01607,and 02460 respectively.Gst was 03460,meaning that 6540% of the genetic variation was found within the populations.The genetic identity among the populations was high,ranging from 09037 to 09723 and averaging 09410.An analysis of 6 populations using UPGMA showed that,there was the closest relationship between Qiubei (YB) population and Wenshan (YX) population,then between Xiaoshao (Y) and Xiping (YA) populations,and the last between Wenshan (YX) population and Tengchong (ZA) population.The genetic distance is almost positively related to the spatial or geographical distance between the populations.

Key words: Erigeron breviscapus