Wafer　warpage　has　been　an　important　problem　to　affect　the　manufacturability　and　reliability　in　Wafer　Level　Chip　Scale　package　(WLCSP).　In　this　paper,　wafer　warpage　evolution　is　studied　for　a　six-side　molded　WLCSP　using　finite　element　model.　A　method　to　mimic　the　actual　fabricating　process　is　presented　based　on　the　＂Element　birth　&　death＂　and　＂Restart＂　technology.　Key　process　such　as　topside　molding,　backside　grinding　and　backside　molding　is　taken　into　account　and　the　results　match　with　the　experiment　well.　The　effect　of　the　parameters　and　structural　parameters　on　wafer　warpage　characteristics　is　analyzed.