The　application　of　manipulator　driven　by　magnetic　force　has　been　more　and　more　widely　in　the　automation　system.　This　article　introduces　an　electromagnetic　manipulator　used　for　micro-assembly　system.　Derived　the　grasping　force　computational　equation　using　the　Maxwell　equation　as　the　theoretical　foundation,　and　simulated　the　characteristics　of　electromagnet　by　means　of　JMAG　analysis　software　to　verify　the　accuracy　of　equation　that　has　been　derived.　Experiments　showed　that,　as　the　important　actuator　among　the　overall　system,　the　manipulator　can　well　meet　the　operation　requirements　of　overall　system.