To　reduce　the　diode　laser　bar＇s　smile　effect　induced　by　packaging,　a　method　based　on　a　chip　mounter　is　presented.　When　the　bare　bar　is　picked　up　by　the　pick-up　tool　(PUT)　of　the　chip　mounter,　the　curve　direction　and　volume　of　the　bar　can　be　measured　by　scanning　the　P　side　surface　of　the　bar　with　a　laser　rangefinder,　and　they　can　be　controlled　through　adjusting　the　setting　up　of　the　PUT.　By　controlling　the　curve　direction　and　volume　at　an　appropriate　state　to　compensate　the　packaging　induced　strain,　the　obtaining　smile　effect　is　restricted　within　0.5　mu　m　steadily.