The bryophyte communities were preliminarily studied by the method of transect sampling from four peak clusters and three slope sections (lower slope,middle slope,upper slope) of karst rock desertification which were influenced by human actions in valley of Siya River,Guizhou Province.The distribution of the bryophyte communities in different peak cluster and different slope section was studied.The results are as follows:(1)The bryoflora of this site includes 8 families,19 genera and 40 species.There are 19 types of bryophyte communities in the area.Among them,14 types are pure communities.The dominant communities are E.julaceum,B.argenteum and H.involuta.(2)There are two very important life-forms,which are wefts and short turfs occurring on the area owing to dry and barren environment affected by human actions.(3)The richness of the bryophyte communities is reducing with the expansion of human action area in this special environment.(4)The results indicated that the E.julaceum has the potential value to control rock desertification contribution which was made by human actions to its highest summed dominance ratio.