Structural characters of leaf epidermis of 20 wild Lilium species were examined by the optical microscope and the scanning electron microscopy.The results showed that:(1) The stomatas of 20 wild lilies are all distributed in abaxial epidermis of their leaf epidermis,which are parallel to the cells of abaxial epidermis ,and located in the endpoint of abaxial epidermis cells.They have no accessory cells,and their guard cells are kidney.The type of guard cells cuticle is striate,and the types of epidermis cells cuticle are smooth or striate.The epidermis cells of all species have waxes which have two types,membranous platelets and platelets.There are significant differences between species in stomata density,size of stomata and leaf cells,pattern of anticlinal walls;(2) L.davidii var.willmottiae,L.davidii,L.lancifolium,L.nepalense,L.papilliferum,L.duchartrei,L.pumilum,L.taliense,L.fargesii,L.concolor var.pulchellum,L.dauricum were clustered in the first group and L.sulphureum,L.regale,L.amoenum belong to the second group while L.tsingtauense formed a distinct group,L.leucanthum,L.leucanthum var.centifolium ,L.sargentiae,L.brownii var.viridulum,L.brownii were clustered in the fourth group using clustering analysis which is accordance with structural characters of leaf epidermis;(3) Structural characters of leaf epidermis play important taxonomic value in distinguishing between different wild lilies.