Abstract: Beijing suburbs wetlands are single and interfered greatly by human activities， thus some plants reduced or suffered distribution atrophy and would become endangered species. This article is based on the analysis about the distribution characteristics and interspecific association of the communities of Glycine soja and Butomus umbellatus in Beijing wetlands， putting forward some measures and suggestions about the situ~conservation activities as a reference combining transect method with sampling method in Beijing wetlands. The investigations and records of the plants in the quadrats included name， quantity， average height and coverage and so on. It calculates the important values of Glycine soja and Butomus umbellatus in the quadrats which are so important value as the basis. Then it made a comparison and variance analysis about the changes of the important values of Glycine soja and Butomus umbellatus in Beijing wetlands at 2003-2005 and 2007-2009 and analyzed the difference and significance between those different data. It made the measure about the interspecific association of the community of Glycine soja and Butomus umbellatus through the method of coupling coefficient AC and chi~square and analyzed the associativity between these two species and the other species in the community. The relation between the species like Mongolia Artemisia， sticktight and Glycine soja or Butomus umbellatus in the community was positive association while the the relation between the species like Bidens Tripartita，sticktight， duckweed and Glycine soja in the community was negative association. The relation between the species like Rhizoma alismatis，hornwort，Malay Pondweed and Butomus umbellatus in the community was positive association. The positive association species of the higher degree of correlation were highly significant correlation in the χ2 test， showing the consistence with the χ2 test. We got the conclusion that there are a lot of interferences and threats which the Glycine soja and Butomus umbellatus in Beijing wetlands facing such as the environmental degereration and so on. There are some feasible countermeasures such as improvement of water quality， recovery of degraded wetland， conservations of the auxiliary species and controlling the population of the competitive species put forward in the paper as references .

Key words: Glycine soja, Butomus umbellatus, community, species association, in situ conservation