Abstract: This paper deals with some plant fossils collected from the Late Eocene Relu Formation of Litang County, Western Sichuan Plateau, by the Scientific Expedition of Academia Sinica in 1982. The fossil-bearinp bed is mainly composed of sandstones, conglomerates and siltstones. From the Relu Formation Eucalyptus reluensis sp. nov., Hemiptelea paradavidii sp. nov., Pistacia sp., Banksia puryearensis Berry, Palibinia pinnatifida (Reid et Chandler) Tao, Myrica sp., Comptonia sp., Albizzia sp., Alstonia? sp., Viburnum sp., and Phyllites spp. were obtained. This indicates that during the Late Eocene the flora of Litang of Western Sichuan, were subtropical in nature mainly composed of Eucalyptus and some evergreen and deciduous broad-leaved trees. The climate was hot and dry. Judging from specimens the fossil locality Litang has uplifted about 2500–3000 m in elevation since Late Eocene. At present Eucalyptus is widespread in Australia. So far no remains of Eucalyptus early than Oligocene have been discovered from southern hemisphere the appearance of this genus from Eocene of Xizang and western Sichuan indicates that Eucalyptus might have originated from northern hemisphere and then migrated via Malaysia to Australia to form a new distribution centre in Australia.