The　paper　addressed　a　practical　problem　of　the　non-uniform　clearance　between　the　outer　ring　and　the　inner　ring　after　the　nosing　process　in　the　assembly　of　spherical　plain　bearings,　the　extrusion　process　of　GEW12　spherical　plain　bearings　was　simulated　by　using　ABAQUS　software.　BP　neutral　network　was　applied　to　identify　the　relationship　between　the　die　profile　and　the　peak　difference　between　the　maximum　clearance　and　minimum　clearance.A　genetic　algorithm　was　used　to　optimize　the　die　profile,　which　yielded　more　uniform　clearance　distribution.　Thus,　the　FEM,　neutral　network,　and　genetic　algorithm　were　combined　to　develop　a　method　for　the　design　of　the　optimal　shape　of　a　extrusion　die.The　experimental　results　show　that　the　clearance　distribution　between　outer　ring　and　inner　ring　is　improved　greatly　and　the　metal　flow　of　the　bearing　becomes　more　uniform.　©,　2015,　China　Mechanical　Engineering　Magazine　Office.　All　right　reserved.