Abstract:Using ISSR method, the genetic diversity and genetic structure of 81 individuals in four natural populations of Chenopodium album L. distributed in four islands in Changdao, Shandong Province, i.e. Beichangshan island, Nanchangshang island, Daheishan island and Xiaoheishan island were studied in this paper. Through the amplification of ISSR with 13 primers, 157 loci were detected. The results showed that the percentage of polymorphic loci was 66.24% with a high genetic diversity (Shannon’s information index was 0.332 0 at the species level); genetic differentiation existed among populations (Nei’s gene diversity was 0.220 1 at the species level); at the species level, genetic variance was 9.27% among populations according to GST value. The genetic distance analysis showed that XHS population and NCS population have the highest population genetic identity, genetic distances and geographic distances have no correlation.