Abstract: Lijiang basin, a N—S spreading fault basin located in northwest Yunnan Province, are filled with the fluviolacustrine or fluvial sediments of Early —Middle Pleistocene. The formation was previously called Sheshan Fm.. In 1993, the author Wang subdivided the formation into Early Pleistocene Sheshan Fm. and Middle Pleistocene Dongyuanqiao Fm. based on the unconformity existing between them and lithofacies as well as invertebrate fossils. The fossil materials described in this paper were collected by Wang from the Dongyuanqiao Fm. in 1985—86. Ihe collections are identified as Megantereon sp., Equus sp., Dicerorhinus sp., Certntitus ultimus, cf. Axis rugosus, cf. A. yunnanensis, Rusa yunnanensis, Rusa sp., Muntiacus sp., Bos sp.. The most taxa (identified as species), except cf. Axis ytmnanensis, are common species for Early —Middle Pleistocene. It seems to show that the age of the Dongyuanqiao fauna may be Early or Middle Pleistocene. However, the unconformity between the Sheshan Fm. and Dongyuanqiao is worthly noted and it plays an important part of determining the age of the Dongyuanqiao Fm.. In west Yunnan, the movement Early Pleistocene and Middle Pleistocene was strong and resulted in the unconformity between the Early Pleistocene and Middle Pleistocene, Up to now, no discoveries of the unconformity within the Earty Pleistocene have been made. Equus yunnanensis was found in the Sheshan Fm.. So the unconformity between the Sheshan Fm. and Dongyuanqiao Fm. was formed during this tectonic movernent. Under the consideration of the fossil mamnuls from the Dongyuanqiao, we suggest that the age of the Dongyuanqiao Fm. is of Middle Pleistocene. Because "Yuanmou nun" was found in Yuanmou basin in north Yunnan, the " Yuanmou man" fauna has been focused by geologists and paleontologists. Now are various opinions on its age. The discovery of the Dongyuanqiao fauna probably provides a new approach to determine the age of the "Yuanmou man" fauna. The Dongyuanqiao assemblage is similar to the "Yuanmou man" fauna. Most of the genera or species from the former are shared by the latter (Table l). The " Yuanmou man" fauna, however, has more primitive taxa, such as Eastylocerus longchuanensis, Metacervulus capreolinus and Muntiacus lacustris. Thus the age of the "Yuanmou man" fauna is relatively close to that of the Dongyuanqiao fauna, may be only slightly earlier than that of the latter, and is about late Early Pleistocene.