Balancing　the　cost　and　processing　precision　of　machine　tool　by　the　method　of　error　allocation　without　affecting　the　machining　performances　is　a　critical　problem　in　the　Machine　tool　industry.　In　this　paper,　a　new　accuracy　allocation　method　for　multi-axis　machine　tool　based　on　Multi-body　system　theory,　manufacturing　and　quality　loss　costs　and　relationship　between　tolerances　and　accuracy　parameters　of　components　is　proposed.　This　optimization　method　is　performed　with　Non-Dominated　Sorting　Genetic　Algorithm　II　algorithm　using　Isight　and　Matlab　software.　A　three-axis　vertical　machine　tool　is　taken　as　an　example　to　demonstrate　the　method,　and　the　optimization　results　show　that　the　accuracy　allocation　method　proposed　is　feasible　in　the　optimization　of　geometric　errors　on　the　premise　of　satisfying　machining　accuracy　requirements.