Abstract: A nonlinear dynamic model of horizontal vibration was derived based on the analysis of friction state on rolling contact interface. The effects of the transform of friction state on the horizontal movement of a roll were discussed. Phase portrait technique was used to analyze the horizontal motion of a roll and determine a limit circle which could describe the path of sticking-sliding motion. The dynamic characteristics and mechanism of horizon chatter were analyzed. The critical parameters able to divide up the sticking-sliding motion requisition in the parameters plane were deduced.