Abstract: The paper discusses leaf micromorphology of 15 species in the genus Osmanthus(Oleaceae) with Scanning Electron Microscope(SEM).The results are as follows:Stomatas of the genus are usually round or elliptical and well organized.Their outer layers mostly have marked margins.In some species,the margins are so complicated that they look like twining ropes.Most species have glands.The outer layers of the glands usually have radiate stripes.The stomata density is 400～1 700 per mm~2,while the gland density is 69～(136 per mm~2).In the following 3 species,O.delavayi,O.didymopetalus,O.urceolatus,there is a particular type of stomata,which is similar to gland.Their densities are 39～146 per mm~2.A key to the 15 species based on the micromorphology characters is given in this paper.On the whole,the results are in accordance with those of traditional taxonomy.However,some crossing conditions have occurred among different groups,so the author belive that it is quite necessary to make further investigation to the genus in order to make sure the usefulness of micromorphology to the taxonomy work.