Karyological studies were made on 12 species of the genus Plagiochila (Plagiochilaceae, Jungermanniopsida) from China. The chromosome number n = 9 was found in all Plagiochila species investigated. The chromosome numbers of five species, Plagiochila fordiana Steph., P. gracilis Lindenb. & Gottsche, P. peculiaris Schiffn., P. salacensis Gottsche, and P. wightii Nees ex Lindenb., are reported for the first time. The results for Plagiochila flexuosa Mitt., P. fruticosa Mitt., P. ovalifolia Mitt., P. pulcherrima Horik., P. sciophila Nees ex Lindenb., P. semidecurrens (Lehm. & Lindenb.) Lindenb., and P. trabeculata Steph. confirmed previous records (n = 9). The length and width of the largest chromosomes and smallest ones are provided. The karyotypes of five species are proposed. The m-chromosome was found in the cytotypes of 10 out of 12 Plagiochila species investigated here, except Plagiochila sciophila and Plagiochila wightii.