Abstract: The purpose of this review is to provide a generally historical background, current advances and research trend for the taxonomy of the eucalyptus with a emphasis on the introduction to the classification of the genus suggested by Pryor and Johnson.The genus, Eucalyptus L'Heriter consists of some 500 species all of which, but E. urophylla and E. deglupta, occur naturally in Australia and on some Pacific islands in the east of Wallace's line.It has almost been two hundred years since the genus was established in 1788. Many botanists made great contributions to the taxonomy of the genus. At present the new classification suggested by Pryor and Johnson has widely been accepted by botanists, foresters and ecologists both in Australia and overseas. The eucalyptus were in their classification arranged in 7 groups and Angophora, another genus in Myrtaceae, was also included in a equal status to subgenus.The new concept of Eucalyptus alliance was set up by Pryor and Johnson in 1981 based on 8 groups mentioned above. A new subgenus, Telocalyptus, and the monogenus, Arillastrum, were added to their system. there are 10 groups, i.e. Angophora, Blakella and Corymbia in Angophora suballiance, Eudesmia, Symphyomyrtus and Telocalyptus in Symphyomyrtus suballiance, Gaubaea, Idiogenes and Monocalyptus in Eucalyptus s. str. suballiance, under Eucalyptus alliance. There is a trend now in the research on the taxonomy of Eucalyptus in Australia that may make these 10 groups independent as genera in the future.