Based on detailed collection and identification of Plagiotheciaceae of Mts. Sygera, four species, namely Plagiothecium latebricola, P. piliferum, P. platyphyllum, and Herzogiella seligeri, respectively, were reported new to Tibet. The morphological characters and geographical distributions of the four species were discussed, and the related illustrations were provided. The voucher specimens were deposited in the herbarium of China Agricultural University (BAU).