In　radio　frequency　identification　(RFID)systems,　excepting　to　identify　the　basic　information　of　target,　how　to　additionally　aware　the　precision　position　of　the　target　is　an　important　and　pressing　research　topic.　In　this　paper,　we　propose　a　novel　range　free　tag　localization　scheme　based　on　phased　array　antenna　for　RFID　system,　called　PATL.　This　method　takes　advantage　of　the　adjustable　radiation　angle　of　the　phased　array　antenna　to　scan　the　surveillance　region　in　turns.　By　using　the　statistics　of　the　tags＇　number　in　different　antenna　beam　directions,　a　weighting　algorithm　is　used　to　calculate　the　position　of　the　tag.　This　method　can　be　applied　to　real-time　location　of　multiple　targets　without　usage　of　any　reference　tags　or　additional　readers.　We　use　a　COTS　UHF　RFID　reader　which　is　integrated　with　a　phased　array　antenna　to　evaluate　our　method.　The　results　show　the　average　is　about　21cm　and　the　time　consumption　also　satisfy　the　real　time　performance.　©　2018,　Chinese　Institute　of　Electronics.　All　right　reserved.