Based on consulting document literatures and specimens， plant introduction， and long-term observation， morphology and other characteristics of Dioscorea simulans Prain et Burkill were anew described and revised. The results show that characteristics of stem above ground twining to left， rhizome below ground， number of flowers in cymule on male inflorescence， fruit reflexed， number of chromosomes of 2n=20， etc. of D. simulans are similar to those of species in Sect. Stenophora Uline， but characteristics of growth pattern of stamen， sex of solitary flower， compound leaf and venation， leaf structure micromorphology， and anatomical characteristics and chemical constituents of rhizome are distinctly different from those of species in Sect. Stenophora. It is suggested that Sect. Illigerestrum Prain et Burkill should be restored， and D. simulans is reassigned from Sect. Stenophora to Sect. Illigerestrum restored.