Abstract:This paper summarized the present research status and advances on the intra- and inter-specific positive interaction, intra- and inter-specific comp etition, niche, and coexistence of bryophytes. Bryophytes are generally the domi nant plants in harsh environments, and there is a trade-off between their water retention and light and nutrient resource availability. Because of the lesser importance of competition in harsh environments, the positive interaction among bryophytes is common, but the intra- and inter-specific competition among bryop hytes and the competition between bryophytes and vascular plants are not rare. C ompetition hierarchy may exist among some bryophytes, but often changes with env ironments. In the process of bryophyte community formation, the random process, nature of colonization, and difference in regeneration strategy can result in th e niche overlap and coexistence of bryophytes, and the niche differentiation res ulted from competition is also one of the mechanisms for bryophytes coexistence. Bryop hytes should not be simply classified as stress tolerated-ruderal life history strategists, and competition is still one of important factors for constructing some bryophyte comm unities and vegetations co-existed by bryophytes and vascular plants.