A　steel　floral　pipe　is　a　key　load-carrying　member　of　pipe　supporting　structures.　It　is　important　to　apply　ultrasonic　guided　wave　technique　to　nondestructive　testing　of　steel　floral　pipes.　Firstly,　the　dimensions　of　PZT　elements　are　optimized　for　the　inspection　of　steel　floral　pipes　and　the　excitation　frequency　of　L(0,　2)　mode　at　30　kHz.　In　order　to　investigate　the　effects　of　the　holes　in　steel　floral　pipes　on　the　inspection　ability　of　this　low　frequency　ultrasonic　longitudinal　guided　wave　mode,　the　relation　between　the　number　of　holes　and　the　characteristics　of　received　inspection　signals　are　obtained　from　experimental　research.　Research　results　indicate　that　the　holes　in　a　steel　floral　pipe　have　almost　little　effect　on　the　peak-to-peak　amplitudes　of　L(0,　2)　mode　at　30　kHz.　As　a　result,　it　is　shown　that　low　frequency　longitudinal　guided　waves　have　potentials　to　inspect　long　range　steel　floral　pipes　nondestructively.　Furthermore,　group　velocity　of　L(0,　2)　mode　at　30　kHz　tends　to　decrease　linearly　with　the　increase　of　the　holes　on　steel　floral　pipes.　These　research　results　provide　a　basis　for　nondestructive　inspection　of　steel　floral　pipes　based　on　ultrasonic　guided　waves　in　low　frequency　range.