In this paper, characteristics of freely frictional sliding motion is investigated. With physical concept and results of numerical computation, we clarify the fact that the trajectories of non-rotationally symmetric objects are nearly straight lines. Further, we expend the results that the translational and rotational motions come to stop simultaneously from the rotationally symmetric objects to the non-rotationally symmetric objects; meanwhile we point out that the radius of instantaneous rotation of the object at final stage is dependent on the final configuration and geometric properties of the object, but independent of its initial velocities. Further, we develop one approximate approach to simplify the analysis of the complex frictional motion for one extreme case, initially translation-dominant motion. Consequently, a series of important properties and motion monotonicity of the frictional sliding motion are obtained. With the above results, an inverse problem that is to determine the necessary initial translational and rotational velocities of the object, is got very easy and straightforward.