The epidermal structures of the sixteen species of Thelypteridaceae were investigated under light microscope(LM).The results indicated that:(1)Their epidermis cells are irregular,with deep sinuate anticlinal walls.(2)All the stomatal apparatuses occur in the lower epidermis,and most of them are elliptical.Altogether 6 types of stomatal apparatus were observed in present investigation(Polocytic type,Axillocytic type,Copolocytic type,Coaxillocytic type,Anomocytic type,Coroundcytic type).And each plant possesses 2-5 different types of stomatal apparatus.(3)The cell size of the leaf epidermis,the form of anticlinal wall,the size and form of stomatal apparatus,stomatal density,stomatal index and type of stomatal apparatus showed some difference between the eight genera of Thelypteridaceae.The results provide evidences for phylogeny and classification of Thelypteridaceae.