Abstract: This study examined species diversity within the moss genus Bryum in Xizang, with a focus on distribution patterns and speciation processes on the Qinghai-Xizang Plateau, while expanding the taxonomic framework for Chinese bryophytes. Specimens were obtained through systematic field surveys, followed by detailed laboratory-based analyses of microscopic morphology and anatomical structure using measurements, imaging, and taxonomic identification, supported by comprehensive evaluation of relevant literature. Two species, Bryum densifolium Brid. and B. teres Lindb., are documented for the first time in China, with B. densifolium additionally representing a new record for Eurasia. Detailed morphological descriptions and high-resolution photographic documentation are provided for both taxa. Observations indicated that B. teres exhibits pronounced ecological adaptability to polar and alpine extreme environments, reflected in both morphological characteristics and reproductive strategy. These findings refine current understanding of Bryum diversity on the Qinghai-Xizang Plateau and provide new insights into bryophyte biogeography and evolutionary adaptation in high-altitude environments.