Abstract: To shed more light on the genetic diversity of AM fungi associated with medicinal plants, soil samples were collected in August 2010 in the 0~30 cm depth soil rhizosphere of 7 medicinal plants in Planting Site, Huozhuang Village and Dahu Village of Anguo City, Hebei Province. caulospora bireticulata was used for spore DNA extraction, PCR amplification, sequence determination and cluster analysis to determine the relationship between genetic diversity of A. bireticulata and soil factors. The 2 fungus DNA sequences from Scutellaria baicalensis and Dendranthema morifolium were used for tree phyletic evolution derived by phylogenetic inference analysis of 18S rRNA gene (partial) to 28S rRNA gene (partial) nuclear ribosomal sequences. The measured DNA regions were 18S rRNA (partial), ITS1, 5.8S rRNA, ITS2 and 28S rRNA (partial). The results showed that AM fungi likely infected all host plants, with 99.2% similarity in A. bireticulata DNA sequences in 3 sampling plots. A high generation stability was noted, indicating a broad spectrum of A. bireticulata. In the 18S, 5.8S and 28S regions,A. bireticulata DNA was highly conservative, with 10 strains having no difference in gene position spot. A significant gene variation was noted in the ITS1 and ITS2 regions. When ITS1 region position spot was located in 291~379 bp, A. bireticulata DNA sequence exhibited 1~4 bp difference. Also when ITS2 region position spot was located in 538~742 bp, DNA sequences for 10 strains exhibited 0~5 bp difference. Cluster analysis showed that the similarities of A. bireticulata DNA sequences among different medicinal plants in the same sampling plot were higher than those among different sampling plots of the same medicinal plant. The similarities in A. bireticulata DNA sequences among different medical plants in the same sampling plot were very high; some as high as 100%. On the contrary, the similarities in A. bireticulata DNA sequences of the same medical plants among different sampling plots were low. This suggested that A. bireticulata DNA sequences were closely related with soil factors. Because of the combined effect of soil texture and host plant, A. bireticulata DNA sequences were remarkably different. The highest difference in DNA sequence was in the Huozhuang-based S. baicalensis and Plant Site-based Bupleurum chinense; with difference up to 7 bp in 1 700 bp.