Aims　at　AOCMT　type　five-axis　ultra-precision　CNC　machine　tool,　the　rotary　axis　geometric　errors　model　is　established　by　applying　the　homogeneous　coordinate　transformation　matrix,　a　kind　of　errors　measurement　and　identification　method　is　put　forward.　It　takes　A　axis　as　an　example,　using　the　function　of　RTCP　to　control　a　rotary　axis　and　two　translational　axes　synchronous　movement.　Different　height　and　positions　are　designed,　and　the　modes　of　the　measurement　are　the　axial,　radial　and　tangential.　The　length　variations　are　acquired,　and　the　relational　expressions　of　deviations　and　length　variations　are　derived　according　to　the　errors　model.　Eight　deviations　related　to　A　axis　can　be　identified　at　the　same　time.　The　method　is　available　through　the　simulation.