A rich mammalian fauna has been recovered at the Shanshenmiaozui site in Nihewan Basin during the past few years (2006~2008). The newly found fauna is the richest and the best preserved ever recovered in Nihewan Basin during the past decades. These materials are not only helpful in understanding the evolution of some taxa, but also are important in reconfirming the chronological sequence of the classical Nihewan fauna; additionally, the newly discovered fauna can also be regarded as important evidences in the biostratigraphical correlations between the two sides of the Sangganhe River as well as between the two blocks of the Youfang Fault.