[Objectives]  To understand the feeding preferences and daily activity rhythms of dung beetles on typical Inner Mongolian steppe. [Methods]  Fresh dung of three kinds of livestock (cattle, horse and sheep) were used to lure dung beetles into pitfall traps in the spring, summer and autumn of 2010. [Results]  Dung beetles were attracted by all 3 kinds of livestock dung but those with different feeding habits had different preferences and daily activity rhythms. The medium-sized paracoprids (e.g. Onthophagus gibbulus, O. marginalis nigrimargo and Aphodius erraticus) preferred cattle dung and were diurnal whereas the medium to small-sized endocoprids (e.g. A. subterraneus, A. immundus and A. comma) preferred horse dung and small endocoprids (e.g. A. comma) were unusual in being active day and night. [Conclusion]  The body size and feeding habits (e.g. paracoprid or endocoprid) of dung beetles were important endogenous factors affecting their diurnal rhythm but the size and physicochemical properties of dung, as well as seasonal temperature variation in the grassland environment, were important external factors.