In this paper, the morphological structure of leaf middle rib cells of 26 species of Bryaceae from the retreating site of No. 1 Glacier in Tianshan Mountain, Xinjiang, China, was studied by optical microscopy and segregation method. The results showed that: (1) the length and width of the middle rib cells, the thickness of the cell wall, and the number of pit fields and the end and tail of the cells reflected that there were some difference of the function and water conduction of the costal cells among same genus and different genera. (2) The end tail of the middle rib cells and the wavy structure of the cell wall could strengthen the connection between cells and improve the mechanical fixation and supporting function. (3) In different habitats, the number of pits on the side wall of the middle rib cells could effectively control the speed of water diversion and material exchange. which might be the positive response of bryophytes in glacier areas to harsh habitats, and had certain ecological and taxonomic significance.