This paper points out the limitations existed in the traditional rules of rolling friction. So, from the view point of tribolOgy a mechanism of rolling friction is studied. The rolling resistance is considered to be dependent on the micro-sliding and elastic hysteresis. Through a series of friction test with metals and nonmetals, the values of coefficient of rolling friction and the rules of its variation have been obtained, from that, its main influential factor is examined. Finally, it is concluded that the determination of the rolling friction coefficient is mainly decided on the practical measurenent.