In this paper, the floor and epiphytic bryophyte biomass was sampled from the dark coniferous forest on the north slope of Changbai Mountain, with an altitude from 1100 m to 1700 m. The floor bryophyte biomass was measured by the method of transect sampling, and epiphytic bryophyte biomass was measured by McCune method. The results showed that bryophytes distributed unevenly, and their biomass changed greatly with increasing altitude. The biomass was the least (543 kg x hm(-2)) at 1100 m, but the greatest (5097 kg x hm(-2)) at 1250 m. The changes of bryophytes biomass could indicate different environmental situations. The biomass change of Hylocomium splendens and Rhytidiadelphus triquetrus with ascending altitude had some relativity with the community character of forest ecosystem. The biomass of Hylocomium splendens increased, but that of Rhytidiadelphus triquetrus decreased with altitude ascending from 1100 m to 1700 m. Moreover, the biomass changes could also show the needed physiological conditions of different bryophytes.