Abstract: In this paper, the toppling process of a non-uniform slender rod in the initial vertical stationary position on a horizontal support surface is studied. Based on the motion theorem of the center of mass, the law of conservation of mechanical energy and the theorem of fixed axis rotation, the expression of the bearing force of a straight rod without slip is derived. It is pointed out that the necessary conditions for a straight bar to be separated from the horizontal plane include two requirements: the mass distribution of the straight bar and the minimum static friction coefficient between the straight bar and the supporting surface.