Abstract: Micromorphological characters of seed coat and aril of 13 species of Sect.Ilicifolia Nakai and 6 species of other sections of the genus Euonymus L.in China are studied under SEM.The result shows that micromorphology of seed coat and aril is mostly reticulate.All the characters of these species can be divided into 4 types,(1) seed coat double reticulate and mesh tuber;(2) seed coat double reticulate and the middle of mesh immersed;(3) seed coat reticulate and aril ruminate;(4) seed coat and aril both reticulate.Micromorphological characters of seed coat and aril provide some proves for relative species.