Ball　screws　are　used　as　precision　transmission　components　in　a　wide　range　of　industries.　The　combination　of　sliding/rolling　motion　can　influence　the　degree　of　precision　degradation　of　the　ball　screw.　Optimization　analysis　of　structural　parameters　can　reduce　precision　loss　and　improve　precision　retention.　This　article　presents　an　optimization　analysis　of　the　ball　screw　to　improve　precision　retention　under　mixed　sliding-rolling　motion.　Precision　loss　of　the　ball　screw　due　to　mixed　sliding-rolling　motion　was　calculated.　In　addition,　the　effects　of　operating　conditions　and　structural　parameters　on　the　precision　loss　were　analyzed.　Factors　affecting　precision　loss　of　the　ball　screw　under　mixed　motion　were　determined　and　the　objective　function　to　characterize　precision　retention　was　established　according　to　imposed　constraints.　Structural　parameter　optimization　of　the　ball　screw　based　on　an　advanced　neural　fuzzy　network　can　reduce　the　average　rate　of　precision　loss　by　approximately　18.36%　and　improve　precision　retention.