A　new　modeling　method　for　multi-axis　CNC　machines　was　proposed　based　on　differential　transformation　theory,　where　the　geometric　errors　were　equivalent　to　the　differential　movement　relative　to　its　ideal　position.　Meanwhile,　the　Jacobian　matrix　was　adopted　to　describe　the　mapping　relation　between　tool　pose　error　vectors　and　compensation　error　vectors,　and　all　elements　in　the　matrix　could　be　solved　by　differential　transformation.　Thus　the　compensation　error　vectors　were　calculated　by　computing　the　generalized　inverse　of　Jacobian　martix.　And　then,　an　automatic　error　decoupling　procedure　was　developed　herein.　Finally,　an　experiment　was　conducted　on　a　five-axis　CNC　machine　to　test　and　verify　this　method.　The　results　show　that　the　overall　position　accuracy　of　the　test　path　is　improved　dramatically.