The　reflection　and　mode　conversion　of　guided　waves　from　oblique　crack　in　hollow　cylinder　based　on　the　finite　element　has　been　investigated　A　steel　pipe　with　external　diameter　70mm,　and　wall　thickness　3.5mm　was　used　in　this　paper　to　analyze　the　reflection　coefficient　of　L(0,2)　mode　and　mode　conversion　to　flexural　modes　when　L(0,2)　mode　incident　at　60kHz,　90kHz　and　140kHz.　The　results　show　that　the　reflection　coefficient　of　L(0,2)　mode　increase　along　with　the　oblique　angle　of　the　crack.　In　parallel,　a　phase　compensation　method　was　used　in　signal　processing　to　extract　other　order　modes.　More　information　about　the　circumferential　location　of　defect　was　obtained　by　this　method.　This　study　will　be　the　foundation　for　quantitative　nondestructive　evaluation　of　irregular　crack　in　pipe.