Abstract:The Northeast Inner Mongolia Autonomous Region is an important soybean production area of in China, and is also an experimental area of genetically modified soybeans. In order to understand the local wild soybean resources? situation and provide reference for safe cultivation of the genetically modified soybeans,we investigated the distribution of wild soybean populations in 61 discontinuous field plots in Zhalantun and Arun of Hulunbuir,as well as Keyouqian of Xingan League. Fifty-four plots(88.52%)were found to have soybeans,including three types: the wild populations,mixed populations of both wild and semi-wild soybeans,and a population of entirely semi-wild soybeans which was discovered for the first time. The sizes of most populations in this region were relatively small,showing ca. 72.2% of the populations being ≤ 1000 m2,and ca. 59.3% being ≤500 m2. The frequencies of wild soybean quadrats were above 80%,40%-60% and below 20% for ca. 46%, 41% and 13% of the plots. From the seeds of 836 single plants collected from 54 wild soybean populations,six seed-coat color types(black,bicolor,brown,brown-green,green and yellow-green)and three leaf-shape types (long oval, oval and lanceolate)were observed. The 100-seed weight of wild soybeans was relatively small,accounting for 84.57% for the type of ≤1.5 g in the total sample,with an average of 1.19±0.49 g. It was estimated that approximately 17.92%,29.48%,and 40.10% of the remaining idle lands may have potential distribution of wild soybeans. We found that the advanced agricultural ecosystem would reduce the density of wild soybeans in populations. The semi-wild soybean was found with higher probability in the long-term soybean growing area. This article also discussed the measures on safe cultivation of genetically modified soybeans in the Northeast Inner Mongolia in the future,as well as the protection of wild soybean resources.