A　cluster　system　performance　depends　on　load　balancing.　After　analyzing　the　load　balance　algorithm,　this　paper　presents　a　design　of　such　a　load　balancing,　algorithms　using　every　working　server　to　sends　a　corresponding　ask　signals　to　balancer　based　on　DUD　principle　and　the　balancer　assigning　user　requests　according　to　ask　queue　which　consists　of　these　signals.　Experimental　results　show　that　the　algorithm　obtains　better　load　balancing　than　existing　algorithm.　©　2010　IEEE.