A　dihydroxyl　phosphate　called　butyl　bis(4-hydroxybutyl)　phosphate　was　synthesized.　The　mechanical　and　flame　retardant　properties　of　TPU　were　investigated　by　different　additive　amount　of　BBHP.　It　was　found　that　with　the　increasing　of　BBHP,　the　mechanical　strength　performance　of　TPU　decreased,　but　the　flame　retardant　of　TPU　improved.　When　the　additive　amount　of　BBHP　came　up　to　12%,　the　tear　strength　of　TPU　was　up　to　maximum.　The　oxygen　index　of　TPU　reached　more　than　27　with　the　adding　quantity　of　BBHP　from　10%　to　12%.　At　the　same　time,　the　mechanical　properties　and　color　can　satisfy　the　requirement　of　TPU.