Dynamic　model　of　the　ball　in　space　for　ball　screw　mechanism　is　established　under　different　angular　accelerations　of　the　screw,　and　non-linear　equations　of　the　ball　acceleration　motion　model　were　solved　in　accordance　with　ball　movement　characteristics　during　acceleration　process　of　the　ball　screw　mechanism.　Forces　and　motion　on　the　ball　were　analyzed　taking　into　consideration　acceleration　state　and　the　characteristics　of　the　ball.　Using　the　existing　structural　parameters　of　the　ball　screw　mechanism　and　accelerating　operating　conditions　of　the　ball,　motion　parameters　of　the　ball　were　theoretically　analyzed　using　simulations　at　different　angular　accelerations　of　the　screw,　along　with　motion　parameters　of　the　ball,　which　included　contact　angle,　helix　angle,　the　ball　center　locus　helix　path　radius,　normal　force　at　contact　points　of　the　ball,　the　tangential　velocity　of　ball　center,　relative　sliding　velocity　of　ball,　and　drag　torque　of　the　ball　screw　mechanism.　A　ball　screw　comprehensive　test　bench　was　used　to　experimentally　measure　drag　torque　of　the　ball　screw　mechanism　under　different　angular　accelerations　of　the　screw.　Changing　regularity　was　found　to　be　consistent　between　measured　data　with　simulation　results.　As　a　result,　acceleration　dynamic　model　of　the　ball　in　space　was　demonstrated　to　be　accurate　and　feasible.