A more detailed comparative study was carried on the leaf form and structure of Saccopetalum prolificum,Miliusa chunii, M.sinensis,M.tenuistipitata and M.balansae.The results showed that in Saccopetalum prolificum, the leaf form, the shapes of epidermal cells,the types of crystal in epidermis,the structure of mesophyllous tissue,the distribution and density of oil cells,and the pattern of vascular tissue in the midrib and so on were very similar to those in 4 species of Miliusa.Therefore, this surported the viewpoint that the Saccopetalum was reduced to the Miliusa and Saccopetalum prolificum was changed into Miliusa prolifica.