Abstract: New rodent material is described from the Bumbanian Gomphos bed in Earlian Basin,Nei Mongol (Inner Mongolia), China. A new genus and species, Yuanomys zhoui, is named. The new species differs from other Early Eocene rodents in having slim and isolated cusps and conules on cheek teeth and transverse paracone and metacone with steep surfaces facing a broad trigon basin. These features of Y. zhoui to some degree resemble those of alagomyids. Constrained magneto- and biostratigraphically, the occurrence of these rodents indicates that the earliest radiation of rodents with modern aspect probably took place during the period of mid-Paleocene to early Eocene.