Traditional　approaches　about　error　modeling　and　analysis　of　machine　tool　few　consider　the　probability　characteristics　of　the　geometric　error　and　volumetric　error　systematically.　However,　the　individual　geometric　error　measured　at　different　points　is　variational　and　stochastic,　and　therefore　the　resultant　volumetric　error　is　aslo　stochastic　and　uncertain.　In　order　to　address　the　stochastic　characteristic　of　the　volumetric　error　for　multiaxis　machine　tool,　a　new　probability　analysis　mathematical　model　of　volumetric　error　is　proposed　in　this　paper.　According　tomultibody　systemtheory,　amean　value　analysis　model　for　volumetric　error　is　established　with　consideration　of　geometric　errors.　The　probability　characteristics　of　geometric　errors　are　obtained　by　statistical　analysis　to　the　measured　sample　data.　Based　on　probability　statistics　and　stochastic　process　theory,　the　variance　analysis　model　of　volumetric　error　is　established　in　matrix,　which　can　avoid　the　complexmathematics　operations　during　the　direct　differential.　Afouraxis　horizontal　machining　center　is　selected　as　an　illustration　example.　The　analysis　results　can　reveal　the　stochastic　characteristic　of　volumetric　error　and　are　also　helpful　to　make　full　use　of　the　best　workspace　to　reduce　the　random　uncertainty　of　the　volumetric　error　and　improve　the　machining　accuracy.