A vector synthesis algorithm was proposed to realize the fusion of tangential and normal friction vibration with the vector theory,and the synthesized friction vibration was researched by the runningin wear test.Result shows that the amplitude of synthesized friction vibration experiences the change from high to low and then steady in the runningin process.The amplitude of the synthesized friction vibration is large in the beginning of the runningin process,then is in decline when runningin continues and produces a stable and smooth fluctuation when reaching the runningin.The vector synthesis algorithm proposed can realize the fusion of tangential and normal friction vibration,and the synthesized friction vibration can reflect the feature variation of the runningin wear state of tribological pairs.