The Yuanmou Basin of Yunnan Province is a hotspot for the research of early hominid evolution and its environmental background. During the implementation of the Program "Research of the Origin and Evolution of Early Man and Its Environmental Background" from 1998 to 2001, a huge quantity of hominoid and mammal fossils were collected. The present report systematically describes an Euprox robustus sp. nov. identified during the recent laboratory work on the collected material. Euprox is a group of earliest cervids with true antlers. The new species is the third one of the genus discovered in China. Judged by its morphologic characteristics, the new species feed on juicy and tender leaves of dicotyledon. It implies that the vegetation of its epoch in the Yuanmou Basin is a kind of southern subtropical evergreen forest and the climate is humid and temperate with evident seasonality. The latter is mostly influenced by the monsoon and secondly by the latitude.