The　dynamic　characteristics　of　joint　interfaces　have　significant　effect　on　both　static　and　dynamic　behaviors　of　the　whole　machine　tool　structures.　A　test　system　for　identifying　the　unit　area　dynamic　characteristic　parameters　of　Fe-based　joint　interfaces　in　still　and　motion　states　were　represented　based　on　Equivalent　Single　Degree　Of　Freedom　(ESDOF)　system　theory.　Compared　with　the　stiffness　and　damping　parameters　in　stationary　state,　the　stiffness　is　reduced　and　the　damping　is　increased　in　motion.　When　the　velocity　increased,　the　equivalent　stiffness　and　damping　parameters　of　joint　interface　are　both　increased.