Bryological field investigations were carried out in the 6 nature reserves of Southern Greater Khingan Mountains during 2009~2012.We collected and identified approximately 1 800 specimens,then calculated and analyzed bryological composition and floristic characteristics of this area;similarity coefficient and euclidean distance of 10 mountains;the diversity index,the species richness,the evenness index and dominance index of 8 kinds of habitat.Our objectives were to provide basic data for construction and management of nature reserve.The results showed that:(1)There were a total of 330 species (including 15 varieties,2 forms and 1 subspecies) of bryophytes belonging to 134 genera and 48 families,among which there were 38 species and 1 varieties of liverworts belonging to 21 genera and 16 families and 274 species,14 varieties,2 forms and 1 subspecies of mosses belonging to 113 genera and 32 families in the 6 nature reserves of Southern Greater Khingan Mountains.(2)Reported 4 species new records of China (Grimmia longirostris Hook.,Schistidium lancifolium (Kindb.) Blom.,Bryum laevifilum Syed.,Homomallium adnatum (Hedw.) Broth.and 12 species new to this area.(3)Dominant families (e.g.Pottiaceae) in this area are adapted to arid habitats.The statistical analysis of the flora elements indicates that it has an absolutely dominant majority of north temperate elements and a proportion of East Asian elements,numbering 60.79% and 16.19%.(4)The region had the highest similarity with Northern Yanshan Mountains and Northern Greater Khingan Mountains;changes of the habitat conditions have certain effect on bryophytes diversity,which is the highest in wet soil habitat and wet rock habitat,the lowest in aquatic habitat.The study reflects that the bryoflora of Southern Greater Khingan Mountains is a transitional zone connecting North China region,North-Eastern China region,Inner Mongolia-Xinjiang region and Yinshan area;compared with Northern Yanshan Mountains and Northern Greater Khingan Mountains,forest density and humidity caused less distribution of the ground vegetation of this area.We suggest that nature reserve should be established in this area to protect transitional ecosystem of forest and grassland,establishing nature reserve also plays an important role in protecting wildlife groups and reproduction of rare and endangered species.